@katespellbound There were a few reasons why I made Yang bi and Sun gay.
Canonically, Yang expresses interest in guys as early as V1.E3:
Yang: It's like a big slumber party!
Ruby: I don't think Dad would approve of all the boys, though.
Yang: I know I do!
Now, assuming that Rooster Teeth isn’t queerbaiting their audience, then there’s good reason to think that Yang and Blake are interested in each other, meaning that she’s attracted to men and women. At the very least, Yang is bi, or perhaps even pan.
My decision to make Sun gay, on the other hand, is in direct contrast to everything we’ve seen in the show.
As far as I can recall, the only time we’ve ever seen Sun flirt, it’s been exclusively around Blake. No shade to any Blacksun shippers, but I’m not overly fond of the pairing, and I always found their interactions kind of—well, boring, I guess. I’m sure someone could pull up a quote that would contradict me, but whenever I think back on any of their conversations, they always seemed to be about either the Faunus or the White Fang. It never felt to me like they had much in the way of chemistry or common interests.
I figured, well, since I’m basically disqualifying all their interactions as proof of Sun’s sexuality, then I guess it’s free game. Let’s make him the gayest bastard that ever lived.
If nothing else, it’s fun to subvert the trope of macho ladies’ man with chiseled abs who has screaming fangirls.
(That, and I also really like Seamonkeys. I might be a little biased.)