Well it's not the crazy idea, but to my knowledge Marie is the only one actively seeking out a relationship with Dylan. It's not even one that's avoidable so far. Not matter what choices you make playing Sophia's POV, Marie ends up asking if Sophia can bring Dylan to the next Yoga classes. I assume Sophia will bring this up during the next Sophia/Dylan event.
Next I'd guess would be Emma, since that's the one Sophia is pushing for. And the one we know has an event soon.
Amber I'm not sure about a timeline for, or even how L&P will work it into the boarding school route, especially since as far as we know she's happily married to Neil. But I hear Dylan/Amber is possible, which is why it's in my list.
As I've said repeatedly, I think Sophia/Dylan won't be until the final days of the game, so almost certainly not Dylan's first, but probably last in the game. To my knowledge Sophia has shown no attraction to Dylan as yet, but pushing to set him up with another girl so he can learn for himself.
And I don't believe Dylan has a chance with Ellie or Patricia. Ellie still doesn't like Dylan (even playing the bonus storyline she calls him a pervert), and Patricia's rule is that she can fool around with whoever she likes, just no dick in pussy. Christine I don't have the foggiest, but she does have a boyfriend, so I doubt it.