I believe that Eunji is bi because of this:
Members start listing off their ideal types at: 0:39
Her answer is so vague, while other members said specifics (Naeun even implied physical features) and have actually said "man". She seems very laid back as a person and open that she wouldn't mind dating either gender, on top of that, I've been thinking. Eunji has a lot of friends, like a shit ton of idol friends. And apparently she's had a ton of dating rumors with guys (guys she's friends with from what I know) (and I believe that she's dated them), it wouldn't be too far off a stretch to say that the same could be applied to women.
Apink members I am currently kind of sure of are Eunji and Bomi, but then again, I've been suspecting other members too. Like, a person on this thread suspected that Bomi and Namjoo were dating and I read the entire thing so I kinda thought about it. But then the Chobom thing, idk. Like, Chorong and Bomi had a livestream together with Moonsun and Moonsun is basically canon at this point, the first thought that popped in my head was: double date. Maybe I am too delusional, but Idk. Mamamoo are all hella gay and lgbt friendly and if I was a gay idol, I would want to be friends with someone whom I can be open to, whom I can be honest about who I am and who I love.