If Clem’s straight, that’s great! If she’s lesbian, that’s great! If she’s bi, that’s great, too! However, I’m not sure how much Telltale would delve into sexuality/relationships. Relationships have never been the main point of the game - yes, there was some Lee/Carley, Kenny/Katjaa (now Sarita), Walter/Matthew, and Rebecca/Alvin, but they were never the main focus. The main focus of this game is, and has always been, survival. It would be great if they did go into sexuality, but I understand why Telltale doesn’t make it one of the main focuses. They want this game to be about a girl trying to survive in the zombie apocalypse, really. If they do talk about Clem’s sexuality, I’m not sure how much it would be focused on, or if they would go farther, or who even knows if Clem cares/has thought about her sexuality. It might be slightly out of place if suddenly she wonders if she’s straight/lesbian/bi, since she’s never talked about it before, and she seems so focused on other stuff. Her main focus is getting to Christa or just surviving.
So, like I said, it would be great if we found out if Clem was straight/lesbian/bi, but I don’t know much it’ll be talked about, that’s all. People can make whatever headcanons they want, but we don’t know if any of them will come true in the game, since relationships/sexuality hasn’t been the main focus.