The distance won't be a problem soon with them coming to MS. It could be kinda hot though if Erynn turns up the heat and tries to seduce the MC away from Nikki/Cara. Literally about to give the MC a blowjob and is like "Oh wait I shouldn't while you're with Nikki/Cara" then you get the option to break up with them or not for the blowjob.
She should remember them, she met them, Erynn was told by the MC that there is a relationship... she should say something, stand her ground.
And then you can pick your poison, promise to get rid of the sisters(with options to follow through or keep lying) or tell Erynn "I'm sorry but i think we should stay friends".
Right now Erynn is very unresponsive to the sisters presence.
I think that will all come to a dramatic end one way or another when they move to MS. Either way it's going to be brutal and plenty of drama to go around.
The MC sold himself for a lot less, he can send Lexi packing for the chance to hold hands with Val XD
When you tell Val that you are gonna break up with Alexis to be with her, the option to tell Alexis "bye bitch" opens up right away(you can also be a scumbag and lie).
The problem is when you promise Nikki the same thing... the option never opens, dates keep happening, nothing ever comes up.
Again the game is unresponsive to what you do with the Morgans.
If you keep pushing towards a big Monroe vs Morgan war, awesome, it should be a lot of fun

, both girls thinking they are the "only one"
But the game should provide options to avoid it, like it did with Val.
Specially given how "sticky" the Monroe girls tend to be.