At this point I think the most obvious way the story can go is:
You (MC) know you have to leave Monica, Jenna and Katie to get your hands on the will...
But any or some of them need to seduce (or maybe get impregnated by) you and then kick you out to get their hands on the will, thus leaving you with nothing. I would vote for Monica knowing this, but I would not rule out the girls or even the friends are helping with this.
This would exlpain why Monica is flashing her assets around from day one and why everbody wants a piece of MC (either that, or this is a adult porn game, one at least must be true).
And it would also give a hidden reason behind the girls to be extra nice to you (apart from MC having a huge dongle). After all we do not know who else is in the will, so it could be anybody with sick/hurtful conditions imposed by the father.
As for all the groupings, many groups do not make sense long term, but, hey!, the Cinderella story ends when they get married. I mean, Monica and Zarah could bang MC together, it does not mean they have to live together forever. The same applies for other groups. In real life, many people bang in groups but very few if nearly none live in relationships with more than one other person (where both are willing).
Even banging Lily and Debbie would probably not last in the long run, the longest I could band my girlfriend and her lesbian lover was 4 years (dramatization).
