for #3, putting a bathhouse or stockpile on a pleasant area goes a long way. Everyone worships me passively at this point lol, as for the pain that is REV UP, try using the mana salts. Similarly, you can get fresh energy and redraw with one of the inspiring brew - it needs spices, so stockpile them every time the market refreshes and get all the base energy brews you can too. The crafting system lets you make both, and with a high-level crystal mine you'll be drowning in rev up in no time. The dev also points to the new research bonuses being a late-game thing but I aimed for higher XP early and a few attacks and my main defenders got ahead of my keeper pretty quickly, they slice through invaders like butter
You can reroll the properties of a tile by destroying it and rebuying. Destroying a tile brings the price back down - so you'll be paying the same price you did the first time when rebuying, not the next price up the ladder. Stacking a diligent worker on a good mining tile gold mine at max level is very good and worth spending all the gold you can on early. Yuna, the goblin maid, is diligent. Green crystals can give inhabitants diligence so it's worth occasionally dumping a few dozen into an inhabitant to try to get diligent - but it can downgrade weapon skills so be careful with your main defenders.
If you start having issues with infighting, set up stages and invite the angry folks to court - watching someone dance increases relation with the dancer, so you can let them passively entertain eachother to improve relations.