J.J. said that the inclusiveness includes people of different sexual orientations, opening the possibility of there being a gay character in episode 8. And there are gay characters in the new canon books/comics apparently. Of course, those aren't as high profile.
Then again on second thought all indications show Luke as being straight up til now, with possibly going Jedi Celibate as of Return of the Jedi. Maybe it would also be better to simply introduce a new character and have them be gay. That way it doesn't look like you are radically changing a character for sjw brownie points, for the sake of doing it, etc. Could also be an issue if Lucas always envisioned the character as straight. We don't want a repeat of the Sulu incident. So yeah, a new, gay character would probably be the best way to go about it.
I've also heard people say that sexuality isn't imortant in the SW universe and that the only ones we know it for are the ones who continue the Skywalker bloodline. This is true to an extent, but Lando clearly showed interest in Leia, and Finn showed interest in Rey. Either way, they're going to have to find a way to address this - Rey's lineage. I doubt it would sit well with the fans if Rey's parents are simply two rando deadbeats that marooned her on Jakku, regardless of original intention. Rey's parents are going to have to be somebody, her father likely being Luke. Otherwise, the only Skywalker of the new generation in the current trilogy is the evil Kylo Ren. Not sure how that's gonna fly.