So my understanding is:
Owen's species isn't all that huge, so him going across the entire chunk of universe and running into someone that has the same blood as his means he is breedable, but Owen imprinted on him because he was (same species+attractive to him+make him jizz and now they're mated??), so it sounds like Nux accidentally took part in a mating ritual with Owen without realizing it.
I think OG Owen might be the only one that can actually make copies of himself.
It looks like - given all the pretty colors that tend to show up whenever they are getting it on or turned on, Owen's species reproduces it a zanny way that we will find out about...NGL, kinda expected Nux to get preggo, but this manga is kinda turning into a Reverse!Omegaverse where Omega get pregnant but also top, and I'm here for it.
Sounds like all the Owens are linked through their minds and bodies in some way, but they all have distinct personalities, memories, and goals - sometimes they overlap, like with then all trying to aggressively bone Nux, but they are for sure unique individuals who all want to be the one actually getting Nux to do what they want rather than passively experiencing it. It was just less clear because Own and Asp are identical, but now that we have Military Daddy Owen and his....distinct tastes (lol) around, as well as his brief explanation on their connection, I think it's going to be more clear where they overlap and differ soon.
About the 2 Owens together: My own theory that has little to no evidence to support it: I think they are both there because the university is working on something essential to why there are so many Owens. They might be making another gate, or perhaps they have a hand on why Nux was born (given the fact that Nux has zero clue to his heritage, even though his species might have a unique way to reproduce). They need two Owens both pretending to be the same Owen so they can do some sneaky spy shit and figure out whats going on at the university that they weren't aware of...
Yeah... At some point, I need an explanation. So Nux is part alien and Owen recognized him immediately. I'm assuming they're mates but Nux never got the memo. Just how powerful is the OG Owen over the others? How did Owen get pregnant? What's the relationship like between all the Owens? They're all the same being and share the same experiences but they get jealous of each other? Why are those 2 Owens together managing a university while everyone else are doing different jobs in different galaxies?