[member="Davin Skirata"]
By all means, lets set something up
[member="Llkt'tudrin'wyshd"]
If we go by canon, it's unclear what the witches think of outsiders though it would seem its only Dathomiri Zabrak.
But, I want to be inclusive and at this point in Chaos history, there have been plenty of non-dathomiri characters accepted into the ranks so I would be okay with an alien outsider joining! Whether you want to make him a male Zabrak instead is up to you
That being said, in order to be accepted, he'd have to fold to the Dathomiri culture. As an alien outsider who is unproven that means he is basically walking into a position where he is of lesser standing because he is male and must prove his worth to The Covens to get any respect and power.
By that logic, the female companion would technically be higher on the totem pole than he was just for being female and as a
non-sensitive she still wouldn't be accepted into the covens. She'd be more like a pawn or servant.
TL;DR yes but he'd be subject to the same sexism as Dathomiri males and would have to prove twice as much as he is an outsider.

I'm more than happy to help you with your character if you'd like to, just shoot me a PM!
EDIT:
The companion could actually become force sensitive by way of Dathomiri magicks, just as Iviss did and the canon Mother Taliz as would your male character. The sexism thing still stands though 