Hi, Act 1 is about saving the first main girl from the act 1 villain who's trying to enslave her.
There's one scene where he sniffs her hair like a creep, early on, however you pretty much stop it straight away. There's also has some stalking elements in act 1 where the villain harasses her, but there's no NTR/no sexual content between her and the villain, even in the bad endings. It's pretty much a happy ending for her if you don't let her die.
Next, all the bad endings in this game are linked to characters dying/girls dying. They're very easy to avoid, unless you're trying to kill them off/see these bad endings. (Pretty much don't abandon the girls or piss them off and you'll be fine.) There's also no sharing of any core girls you romance/no MMF content with them. The only group content in this game is FFM/FFFM/harem content.
The only exception is the ending for the act 2 main villain in the next update after this one, where she has multiple endings and you can decide what happens to her, like sending her off to a whore house/giving her to your friend as punishment because she torturing him/ you're marrying your best friends sister instead and don't want the act 2 villain.
Finally, there isn't any prostitution for the main girls. The only thing remotely close to that, is there's one optional joke character/minor girl who's kind of like the town bicycle who wants to fuck every man in sight/is trying to rape you, but she doesn't have much content in the game yet.