Considering that Cherem Rabbeinu Gershom never applied to non-Ashkenazim...
1) If there was no civil law precluding it, is there any reason non-Ashkenazim couldn't be married to two spouses? If there is something (other than civil law) precluding it, what is it and does it apply to ALL non-Ashkenazim (Sephardim, Teimanim, etc.)? If so, why?
2) Is there anything precluding them from divorcing their wife against her consent? If so, what precludes it? (Ashkenazim are precluded by the cherem.)
I've heard that some non-Ashkenazim had two wives even relatively recently. That some even came to Israel from the Arab countries with more than one. If so, the only thing seemingly stopping it now is civil law (which could change.)