Jay is bae. I honestly found Crystal boring after the shock of the whole "oh wow she has two bodies" thing wore off, and Zoe doesn't have tons to her character. Jay also lacks growth, but I found his interactions amusing, and at least he has the whole 'not-straight guy pining for a "straight" guy' thing. I dunno, it just seemed to help flesh his character out, even though the author hasn't given him ANY substance.
I don't think Janiel will happen; the situation with Crystal is pretty much identical to the Miraculous Ladybug one, and Adrienette [/variations of it] is the most popular ship, which will probably be Canon sooner or later. ML makes for a super profitable franchise, so this is likely how it'll progress. *sighs sadly*
While I wish Janiel had a shot, it most likely doesn't. Jay is still deserving of everything he wants, and he'll always be my favourite, but the odds are stacked against it. The real question? Who should Vasco go out with (because blind date girl is undeserving)?
I swear JayxDeniel got more and more gay by each chapter, in case anyone is wondering, this does not need to be BL to have the gay characters in it,,