I feel like it's pretty strongly implied if not outright stated that Eita goes both ways.
I will say though, and be blunt about it, the game needs a few big girls. Thicc, stocky, chubby, or heck even just a fat girl. The game has such an amazing array of plus sized guys of all shapes, and ranges between beefy and chubby, that it's starting to get a little noticeable that the few female characters in the game have been playing it safe pretty hard. I mean, especially more recent ones like Benten have really cool designs, far cry from how boring Taomaiti's is (I agree, maybe she just needs to be in a story.) and I'm glad they finally put a female kemo in with Hakumen (who looks awesome.), but generally speaking they've been pretty garden variety anime girls. It's a pretty stark contrast with the guys, in a supposedly LGBT themed game rather than specifically gay.
Not trying to be all PC here before someone gets in my face about it, I can't speak for others but being bi myself and having an affinity for larger people, I'm glad for the larger guys but I certainly wouldn't complain about a female equivalent or two if they're designed well. And trust me, it's not like there aren't more than a few artists in the Japanese doujin scene who have that as their thing.