For those that dislike Remilia and Angel because she is just manipulating him, or think it is sad that Remilia only likes Angel because she sees Emi in him...
Yeah, pretty much.
Remilia is basically crazy and the only reason she is not pure evil is because she worships Emi too much to ruin her goals.
Someone some chapters ago made an analysis of Remilia and if I remember right she is basically a sociopath whose only anchor to humanity became Emi. So everything she does has to have Emi as a measuring rod so she does not go too far to the deep end and disappoint her. Thankfully for everyone but those we already dislike, Emi is a great role model.
In canon she would have latched on the prince instead, and when that anchor left her she would have turned all that obsession from worship into destruction.
Basically, Remilia = full yandere. Thankfully the one she is yandere for pushes her to act towards others on the Dere side, her Yan being kept in closed doors in a way her revenge would not hurt Emi's image.
Angel is a tragic person that, on my view, would have been entangled with Remilia for good or ill. Thankfully in this it is for good, and even if the one he is falling for is her pretend Emi it is better than the alternative, where full-Yan Remilia pushes him to genocide and ruins his life too.
Besides, even if he is going to end with a fake Emi I doubt Remilia's actions would let him go for anyone else anymore. Even if he finds out, with his personality I'd like to think he would admire more Remilia's loyalty to Emi than be hurt.
No, the person I think is the worst victim here is Pina. As in, the real Pina. Others mentioned it, but no doubt she is being Remilia'd but by a person much worse than Emi.
While we have no idea what is going on with Emi, even if she disapproves of Remilia's goals we can be sure she would be satisfied with the methods until now (until the final points of the revenge she is applying "the best reveng is living well" to everyone she is not angry towards, after all).
Depending on how long ago Pina was taken over, though, who knows how much shit she saw being done by her own body with everyone thinking it was her. Would she even want to take her body back anymore?