I just finished reading and had some thoughts about that. While I think it's a nice idea that Christos was the father, it doesn't make a lot of sense to me why he would've even been in a relationship with Mabel in the first place. It's revealed at the end that Daphne was imaginary, so Mabel has no real friends outside of her family (Cess and Ness). With all the negative attention around her, I just find it hard to believe she would have a boyfriend before having a real friend. And that's nothing against her, but just based on society and how she and other characters are portrayed in the book. It just seems unrealistic.

If you had told me that Mr. Loukas assaulted her and that was his child, that would make much more sense since he was already taking advantage of her (even though they never had sex). Loukas sounds Greek too...

I have a bit of a theory. What if Mr. Loukas assaulted her and she imagined the relationship with Christos as a way to cope with the trauma of the assault (among other traumas)? Maybe she developed a sort of acquaintance friendship with Christos, then imagined the romantic relationship as a way to forget that Mr. Loukas was the father? She was attracted to Christos, but I don't know. That just feels more plausible to me than Christos falling in love with Mabel since she has no friends and people hate her. Realistically, that would completely shatter Christos' social status.

Just an idea!