Yep, I normally do the same, but I did forget about the after prom scenes where you can apparently hook up with the girls when they're in a trance or whatever. Can't say I've viewed them but they don't appear in the gallery either, so if those are real ntr scenes they might not be too bad.
I was wondering, I have seen people mention saving both Emily and Sam I think it was, but haven't come across that. When does he kidnap both?
If you do try to hook up with them while they're in trance through Melvin's offer which ends being a trick then it will add one corruption zeta to their stats which stays there and will open up possible NTR scenes for when you replay certain sections of the game in the next loop.
The indication for this is the option putting emphasis on the NTR with some word play like this: "It's
Not
The
Real Emily".
To add on, the gallery will only have repayable or locked NTR scenes once you got a corruption zeta for one of the girls and
Melvin will then have his own section that will show which scenes you can unlock and the ones you can replay.
For the last part with the question it's a bit spoiler territory since that update just came out so I'll make it hidden in case anyone hasn't played it yet.
There's now prom Emily LVL 2 which has her giving MC a BJ and offering to have sex with him when they get back home, but when they get there Melvin is waiting for them with Sam who's in a trance.
Melvin then commands Lexx to tie up Emily after some arguing and Melvin mentions that she's "next on his list". Alexa does show up to help which leads to resetting the loop to help Sam because they can't take her out of the trance, however like the Sam prom LVL 2 they don't take Emily back due to reasons we don't about yet.