Hello, you're asking alot of questions but I give it a try.
First off, this game is totally different than MoO2 in many ways, so you basically have to learn alot.
1.) The button at the bottom left has sliders for military/social/research. These affect my entire civilization. What are my options to instead control this for individual planets? It's very frustrating to not be able to optimize each planet's production. I know about the focus buttons at the top of the planet, but these seem extremely limited at best.
Focus is the only option.
Although you can specialize planet to have only industry or research by only building factories or labs. You also can re-route asteroid mines to get additional industry although this will most likely decrease their value.
2.) Seems like if I had, for example, 50 max social production and 10 max research, and my sliders were 50/50, I would produce 25 social and 5 research (30 total combined output.) Whereas everything into production would be 50 production. Taking the money cost as a given, and looking simply at production ability, this seems fundamentally skewed in how it works. I.e., planets simply can't work efficiently unless they are all one type or the other. Or is that not even possible? (guess it would depend on the options for individual planet focus.) Thoughts?
The Initial Colony building & the Civilization Capital give out both Industry & Research. So actually it is impossible to get both for 100%.
But it is possible to either have all factories or all labs run at 100% of their capacity - it's called playing an "All-Lab"- or "All-Fac"-strategy.
In the All-Lab Strat you put slider at 100% research and only build labs. The planets production come from focus. Because you can only set focus on one item, you will be lacking Social or Military. In this scenario you are technically ahead of everybody, you have very little ships or stuff to play with, but these things are very powerful. You also need alot of money because most likely you'll have to compensate your low production by buying improvements or ships. This money could come from techtrade. You also have to totally ignore asteroind mines because they don't bring you production.
In an All-Fac Strat you only build factories, and set all planets to focus research. Here you can vary your slider to, eg: 100/0/0 (during the colony rush, or if someone declared war on you), or 0/100/0 (when you want to build out your planets and no ships are needed, most after the colonial rush), or 1/99/0 (the same, but planets without a social queue now get the overhaul SP converted into MP), or 50/50/0 which is a balanced approach. If you have alot of points set into reserch the 50/50/0 approach will show you equal numbers in all three fields, and you also have the most liberty playing around with focus - you basically can create a 75/25/0 or 25/75/0 or 38/37/25 or 50/50/0 planetary output, used wisely this can accelerate your output tremendously. For example, if a social project shows 2 weeks left you can make it 1 week by using focus, and this holds true for military as well. Overproduction isn't taken into the next project, so you don't want to overspend too much!
Please note that in a All-Fac strategy does even need more money (mostly because of increased maintenance) and this is making this strategy very hard. But once you got the hang of it it's nice gaming because there is so much to do. It's also pretty powerful. However, you'll be severely lacking research in these games and you either trade techs from other civs or get them through stealing (invasion). With this Strat you can rushstorm the AI.
Or you can combine those two. For example, you alternate between 100% production or 100% research, dependant on what you need most. For example, when you have researched enough techs to progress your game it's usually best to put these techs to work by investing fully production. Inversely, if your techs are inferior to the AI's it's most likely pointless to produce alot of stuff, so change back from production to research.
In my games I flip between production and research many times. I usually play an All-Fac with the exception of using labs on research-bonus-tiles. I also try to maximize my population to, at least, 15b ppl and build so many economic structures so I am able to always upgrade my ships to the latest design.
Structures that give moral, population growth, economics, or influence work independantly of your global sliders and therefore always give you a 100% return, that's their advantage.
3.) I see that if a planet has no social projects, production designated for social is automatically diverted to military. But it seems the reverse is not the case. Is there any way to designate production to divert between the 3 types for each planet? (if so that would help with #1 also)
None. Please also note that whenever Social overhaul into Military is happening you are facing some loss of production, because the overhaul isn't multiplied by the racial bonus. If you are playing a mixed slider setting strategy you can avoid that by sliders 50/0/50 and setting social focus on all planets that have a social queue. Once the planet is outbuild you either focus on military or research just as you need it. This is a very good approach for beginners because the game develops harmonically and you still have alot of divers options in how your planetary output is.
4.) After a few short plays, it seems like economy/money is a million times more important than anything else. Without tons of starting economy boosts, it's just a constant struggle to stay solvent. Whereas with enough money I can produce like crazy. Should I basically always put 4/10 points into maxing economy with any race? Should I then put further points into morale etc. so I can tax more, and subsequently support even more structures without running in the red?
Actually the most strongest normal bonuses in the game are Military Prod, Social Prod & Research Prod. Money is only important because you need it to fund these 3. Once this is established money looses alot of worth.
If you want to buy something you'll have to pay 10 times the amount of money as if you would fund a production with this money.
Generally you want to have as many factories and labs as possible, only building banks if needed. But in the early stages of the game this isn't possible because money stems from population, and your population first has to grow.
Therefore building banks at low populated worlds also doesn't net a good return.
The first thing to focus on is population growth + moral. Try to avoid all buildings that have a high maintenance. The initial planetary production & research is enough. Try to get as many planets as you can, afterward grow their population and then, build banks. Once a positive, ever-growing economy has been established get production up.
Investing into economy + moral + pop growth is "most easy" and I would recommend it for beginners, but it is not so strong in the long run as if you put points into Mil, Soc & Res.
5.) I read that you start off as a dictatorship, and that approval "doesn't matter" until you get other governments. Is this true / can you explain this?
Once you get another government you'll have to vote 2 times a year, and if your global approval rate is too low you'll most likely loose this vote and then loose the benefits of your political party and even get more penalties installed. But the game only looks at the approval of that specific turn, so you simply lower taxes the turn before and are safe. Also, in an improved government you'll have to vote before declaring war.
6.) What's the first tech which gives better factories? Should I prioritize it?
No. In DA the very best filler social project for the early game is the "Fertility Clinic". It's cheap to produce, low maint and brings your planets up in no time so you can overbuild these Clinics with other stuff. Don't use them when playing Torians.
8.) My starting miner on auto, once it has built a single 5-turn upgrade to each asteroid, proceeds to fly off into unknown space to do god-knows-what (I assume it's going to the nearest asteroid.) Should I do something else with it? I can't seem to figure out how to further upgrade the asteroids (I'm assuming I need a better tech first.)
Asteroid Mines that are too far away bring in nearly zero bonus. Most likely they rebel anyway, so forget this. Either park your Miner at your system and research "Space Mining" or upgrade the Miner to a Colony Ship on the second lease for only ~50bcs.
Later when Asteroid Mining becomes more important you can build some Miner on a small/tiny hull. They don't need range or speed or anything because usually they sit at one plance anyway.
7.) What are the bonuses for keeping certain amounts of money in the bank, if any?
None, but your economy gets a -20% penalty if you end a turn above 19.999 bcs.
9.) I've tried several games so far, exploring 10 or so systems around my home, and have found almost no high-PQ planets. I've seen people say to not even bother going for PQ4-5, but then I find maybe only 1 planet better than that. Is this normal?
I will always try to get any planet in reach regardless of PQ. Initially PQ doesn't even matter because you don't have that much money to fill them up anyway, and later these planets can be terraformed. Some grow quite large.
But as long as a planet isn't PQ8 or more don't build farms on it, because there's a cap on population dependant on the planet size. LowPQ worlds are best used with a starport boosted by factories. No fancy stuff there.
10.) The influence & trade stuff is interesting, but part of me wishes I could just play some games of this like I do in MoO2, being xenophobic and just focusing on colonization & industry and a military victory. What would be some good possible settings to help with this?
Disable techtrade, uncheck all victory conditions, blind exploration, take a medium galaxy, common everything, put some Minor races in there, normal techspeed and just go for it. Korath & Drengin are the best races for early war. With Drengin you declare war every turn on 1 (ony 1!) enemy and you take their SuperDominator Corvettes to destroy everything. With Korath Spore you are not bound by your own population to grow before invading.
However, early war is difficult because you still have to fund it. Here, playing Torians is the best option (keeping moral at 100% on all planets). With them you can basically skip the pop growth and econ phase and go research directly into weapons, invasion and prodcution.
Most civs go to war after year 2 so that actually gives you alot of freedom to annex some Minors or your neigbours with +1 attack ships.
Nevertheless, these one-sided games are very weak in a lot of regions. Usually it's best to get all the techs in the techtree which hold racial bonuses and try to stay out of trouble and silently militarize up and only declare war if you're sure to defeat & swallow the AI without wrecking your ships.