Here's a question for you; who would win if a Flood Colony went up against a Xenomorph Hive? Which one would be able to assimilate the other?

I don't know. Xeno's are creatures who's sole purpose is to kill and breed that's about it. Flood are a parasite that assimilate sentient life forms,absorbing in cases skills and memories. Not really sure how sentient a Xenomorph is exactly,since they seem to operate on pure predatory instinct with the exception of the queen. In truth two very divergent life forms. Who knows. A Xenomorph is not your typical Carbon based life form in fact not even sure they are carbon based but The Flood are not your typical Parasite so who knows.