Also, there was the scene where Ellie looked at gay porn mags and had no interest in the naked men at all beyond the absurdity of the magazines.
I mean, that doesn't prove she was gay and from that context alone I wouldn't assume anything, and in fact the game developers hadn't decided one way or another at that point because… it didn't matter. But hey, it was there, if you absolutely need something other than the DLC.
But really, "straight" doesn't have to be the default norm, any more than "white" does. If someone is "other" it doesn't require a story point, it can just be... not the default.
Anyway, onto Ninty.