It was hinted that Monica had a secret, but it was some time ago. I think for her to become a baddie would be too much of a believable plot turn around - could someone be as naïve as she seemed when Zarah set her up early on, and then be up to no good.
The café owner is the big question mark?
The other dodgy question though is why was Bella using Elaine's bedroom and bathroom?
Having 'forecast' the closet scene (well forecast may be a bit strong)
I am now waiting for the MC to bang Monica in Zarah's house next episode.
There is so much interaction in each episode the MC can still add more pussies to his harem, and then there is still loads of future plot lines with permutations of threesomes or more.
This story is so well crafted - too many of the others seem to progress with the MC reaching progressively more 'bases' with each of the females all at the same time:
Handjob from all the girls - Check
BJ from all the girls - Check
etc.
Pity the social experiment failed, but Cheeky came through with enhanced rep.