1. I shouldn't think so, but I haven't explicitly tested for this either. I'll try to do a quick test for this sometime by making York 100% Muslim

2. You mean buildings destroyed when you sack/genocide a city ? There's no such variable that I've seen - yet. My knowledge of the different .txt files is none too shabby, and still I find new stuff all the time

3. Again, haven't seen any defined modifier or setting relating to this, and if there were I'd assume they would be in descr_campaign_db.xml or maybe descr_settlement_mechanics.xml , both of which I could by now almost quote verbatim by heart

4. I'm sure alpaca or some other scriptomancer out there could whip out a code snippet that would do this if asked nicely, but I don't think a) such mechanism is in the vanilla game b) it'd be as easy/straightforward to put in as copy/pasting a line here and there or fiddling with existing variables.