He's definetly gonna choose Yuno. He's gotta.
I just read this all today and I wanna know what happened to Yuno in the past as well, but that'll probably come up closer to Yuno and Yuki being the last ones left, in fact I think it'll end with them fighting, Yuki winning, becoming god, and LOL RESET and Yuno is alive again along with the others...maybe. That or both lose and the terrorist becomes god.