1) How on earth (or whatever planet ) do I stop my people from randomly dropping to 60% approval? It's like I'd have to fill the planet with extreme stadiums and ish just to get them to stay at a reasonable level...
As far as I know the things that affect approval are a high tax rate and a high population. One common mistake is to build too many farms. So far I've played the game and won at crippling difficulty and can see no real need to build more than one farm on a planet.
I don't bother with morale buildings at all, the initial xeno entertainment tech gives you a civ wide 15% bonus and later ones give a further 5-10% in total iirc. These combined with the morale/approval trade goods and (if you're lucky) a morale resource, mean you can get a very good bonus which should more than suffice for most games.
Also assuming your overall approval is high, 60% on planets which already have a high population isn't that bad and in the overall scheme of things won't make that much difference.
2) How do I delete old ship templates from the game, I don't see them anymore in either tab in the shipyard YET when I research technologies related to them I see them on the list .
Never tried it - so I don't know.
3) Is it basically a give in that small ships are not going to have boosters or armor or anything like that? I sometimes feel like I'm missing something obvious because I swear the AI always has better ships than me.
The AI may have bonuses you're not immediately aware of - a military resource or a race advantage with weapons/armour. But generally small craft don't have enough space to be anything other than flying missiles. Don't underestimate them though - in large fleets they can be devastating and if you have them in the AOE of a military starbase it's easy to magnify their effectiveness.
As the game progresses and you improve your miniaturisation they will be able to support armour and more engines, but by that point I usually have so much production that I produce medium+ ships instead.
4) Is there any way to take a rank 0 planet and up it? Any sort of gaia transformation option ala Master of Orion 2 ...that was a sweet tool.
No - though some special events will make such planets habitable. These events are so random that it’s not worth taking them into account.
5) I assume military slider is for building ships, research is for ... research, and the social is for building buildings? Do any of these three sliders make people love me? I need a fourth slider for "pleasure palace" or something.
The closest you'll get to a pleasure slider is the tax rate - those citizens love low taxes.