I can't help with most of your questions, but for the last one, that's a perfect application for NAPs.
If you enact Roughhousing Encouraged in one neighborhood and Free Love in another, you'll have plenty of fights and resulting enemies anytime you spend time in the Roughhousing neighborhood. The enemy relationships will then persist whenever those sims run into each other elsewhere.
In the Free Love neighborhood, you will have oh so very many pink bars developing between whoever, but no one will actually object... until, that is, you spend time in another non-Free-Love neighborhood and sims start acting on their pink bars there.
