IF even NICK APOSTOLIDES (Leon's VA who worked directly under Capcom during the film-making of Infinite Darkness) says that Capcom left it in the open about where Leon and Claire's relationship can go from there. A "very intentional move by Capcom" (leaving us on a cliffhanger), means even Capcom supports the fans of the ship to continue shipping it.
Continue enjoying it. It is not an IMPOSSIBLE ship.
It is a very plausible one for even Capcom to kinda make it a complicate thing between them. Their relationship is complex, then. Meaning, they (CAPCOM) and WE can do with it as we want! Personally, the Sexual tension (as Nick named it) between Leon and Claire, plus all the flirting they had in Re2Remake kinda makes it plausible that Leon and Claire are, at least, friends with benefits, y'know?
There is a lot of trust between them and they're very comfortable with each other being playful, winking at each other, and even commenting on their outfit (am I right, Claire~?). That is not something you do to just ANY friend, (Or to ANY friend at all).