Yeah, we could rescale costs up: 3x
And then add a bonus of: +100% Income tax bonus to settlements to start.
Your "capital" can be given a larger bonus. Very important for some factions, if they are AI held, it can help small factions).
Then switch buildings to give +% Income tax bonus for the economic ones, and the happiness/mulitary buildings will give you -%income tax bonus.
You can use mines (for gold/silver at least) but a more general mine building might as well just give you +% income tax bonus. I would target a payoff time of maybe 15-20 turns for the early structures, but longer for the more expensive ones. +% tax bonus may be stronger in settlements with more population; at the same time, having a penalty hurts more, and you need more happiness buildings for a larger settlement
Trait/Ancillary wise, having governors gain traits/ancillaries that increase tax income would be a nice reason to encourage governors. Note that if these are powerful, nerfing the capital bonus will be necessary.
Farming Levels, Public Health are annoying bonuses, FYI. Probably change them for straight happiness/population growth bonuses. You can have population control buildings that work on that. Law is a relatively nice bonus (reduces corruption) so it should have higher costs if you want them.
As a bonus, if the bonuses are mostly Happiness instead of Health/Law, you can pretty safely use -Happiness on buildings you want to be extra painful...
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You can't repurpose the mining/farming trees (and are restricted by # of building trees you can have) so they make natural "mining resource" and "farming the resource" buildings.
The market tree could be used for "tradeable resource" bonuses like furs etc etc.
You could also make available "industry" building trees for industries you like, dependent on having the resource and appropriate extraction built. Eg: Gold/silver smiths, which require some level of mines in settlement with gold/silver. Or wineries, requiring farms to some level.
Note that mining tree buildings CAN use tax income bonus, but can only give mining income bonus for gold/silver (you can make it buildable everywhere I think).