Ok well on this debate let me just say parodox is a man who learned how to manipulate the universe but why would he be more powerful than a species who’s entire shtick is doing just that? And no while technically not omnipotent I think that is only because he lacks the ability to know everything since Ben is in control not a perfect being
Bellicus said for a bit. They don't count time the same way humans do. They never said forever or permanently, nothing of that sort was implied. The rooters arc happened not too long after UniverseVTennyson Ben was still 16 after all. I don't think Ben 10,000 has controlled Alien-X or he would have used him.
It's also possible that maybe the battle between Alien X and Galactic Gladiator didn't take a full minute and so Ben still had a few seconds left during the rooters arc. Or maybe Ben just quickly convinced them again.
We don't know for sure but in the show they said temporary. That was made very clear in the dialogue.