I think all your Rivals have different unique powers to corrupt people. if you look at the bad end for the mom I think she does stay loyal to the one who stole her from you. at the bad end she makes it clear that she wants nothing to do with you ever again. after the bad end plays out for her you're pretty much cut off from any and all interaction with her after that.
I think I already made one post or two in this thread already about how I think things are probably going to go or whatever.
that's why I thought the idea of conquering your Rivals and gaining/claiming their unique powers of corruption will end up making you stronger than your "current" set of Rivals. but I feel like later on we're going to see some more big bads show up then they will cause more problems for MC. like he's getting a bit stronger than they intended him to get. or maybe they never intended for MC to get the powers to begin with, maybe I think that's what they was hinting at in that one bit of the story where you see the MC's father, talking about some stuff and what not can't really remember the full thing ATM.
also maybe with the angels power we can use it to free someone from someone else's influence and put them under our "protection"
who knows somewhere along the line after we conquer and corrupt/"Save" everyone in town, we probably see the one pulling the strings will show up in fight the MC for control or something
I still believe we should genderbend our rivals after getting victory over them and then "claim" their powers
(making them into traps or futanari is optional but preferred, but making them into just females is fine too.)