Unless something was changed in the meantime, it is also possible to romance Alison and still have threesomes with her. But for this you need a Stag or Chad Ian, something many players here do not play, still it is a viable path.Ian and Lena just fucked in the epilogue. Should they have a scene in every part? Thats difficult to do and not necessary.
Alison scene differs slightly if you romance her (and give her a present to unlock a WIP scene) or are her sexfriend and share her with Jeremy. Do you still need saves or are you already through?