No, it's mostly about preference. There are variables that make the girls say cuter things and move the relationships faster.
I don't have assets for that.
Yes.
There was another question about fetish options. Lesbian action was optional in Candied Oblivion (though the MC was present). I plan to make the less universal fetishes optional. If someone doesn't like exhibitionism they will hate me. I think everyone who played chapter 1 figured out the 
. So, there is unavoidable incest.
A part of me wishes I had put a fetish option in the first chapter so that people would get a feel for it but then people might think that fetish is a big part of the game to come. It's a temporary problem for the first release.
I try to stick to the standards for options that Killer7 and Sisterly Lust laid out for me.