preferences and choices, with the possibility of ending up with different partners (or none), but it will always in the end be a way to work on the MC, Myriam and deepen her character, revolving around the relation mother/daughter.
Will she be able to help realize herself and avoid her mistakes? Will she encourage her curiosity and love? etc...
And just in passing, sorry for all the people asking for the "enslaving" of the daughter and corruption via the mother, but it's not in the cards (for now anyway).
Well, pity for for the "not in the cards" in term of number of possibilities, though I have to admit personally it is anyway not the path I would have preferred (though maybe I would have tried to see how it was).
But excluding that, would not exclude other possibilities.
If Myriam does not have the stats to stop Marc's behaviour (to put it in that way), one leverage Marc (or anybody else, for what matters) could use to convince Myriam to do stuff, would be that otherwise something could happen to Katherine. That does not even really require anything to happen with Katherine and Marc.
Yep, I know, it does not look like a great depiction of Marc, but it does not seem to go against his depiction so far either.
Plus, it does not even need to be Marc. Myriam has already met at least two characters (actualy, four, the motel owner and the three from the underpass) that probably would have no problem to do something to her daughter (or just threaten to do it) to get to the mother, and others may appear to be more neutral, but they were introduced on a very light way, and there can be others to come.
It would not even require to make everybody a bad guy, and the game tags even have already "blackmail" and even "rape", though both can apply to easily to Myriam, Evely, Katherine, Jennifer - and for certain situations to (potentially) happen, even if one has made the choice to push for Katherine as lesbian, it is irrelevant.
So, it all depends on how you have planned the possible paths in the story.
But since you are in the mood for spoilers
;-), even if by saying something is not in the cards...
Given there is already the incest tag, and given the description you had posted about Jennifer, would you say the possibility of, let's say, a certain reinforcement of the mother/daughter relationship ;-) is also not in the card ?
It would not stop Myriam from helping Katherine develop her own path.