Those are non-immigration questions because U.S. immigration doesn't apply to people employed outside the U.S. so any compensation structure would be fine from a U.S. immigration perspective. I can't comment on the tax considerations/issues.

Thank you very much for the reply. I forgot to add:

What considerations should we take (if any) if we intend to support them coming to the states and becoming employees after turning profitable or a successful funding round.

There's a visa specific to Mexican (and Canadian) citizens so there often are easy immigration options/solutions for Mexican citizens.