Yes, I think it could be possible. Think of it like Dalia and Alex from another game.😉
Eternum? I don't recall Dalia and Alex doing anything together in the current content. They just real close best friends and I think Dalia has already stated somewhere she doesn't swing that way. Only threesome stuff in Eternum was Nancy and Nova. But we do know Nancy is onboard and nudging the others into the harem. If anything I wanna see some Bare Witness I think it was called, the harem mash route lol.