Harem route for all accepted (alphabetical order) : Cassandra
D
Elena
Georgina
Jennifer
Olivia.
Use both hands to count, bro...
Cassandra wasn't too bad looking, though I don't see MC having a chance in hell with her (though she seems bi she he had admitted to dating a guy in the past). Georgina, I can't see a threesome with her, D and MC. Georgina doesn't appear (to me) as being very corruptible to the idea.
Olivia, maybe a threesome between MC and D. Though I'd give that about a 5% possibility at the moment.
Elena and maybe Jennifer I can see having a threesome including D.
Only thing is, I guess we'll have to wait and see what the outcome of Elena's discovery (i.e: the cliffhanger) will be. On the harem route, I can imagine she'd be crushed knowing that the guy she was starting to fall for was in bed naked with someone besides her. That's just a theory I have. On the D only route, yeah, I'm drawing a blank on that.