I'm sorry I thought you were suggesting that Stern could get residency in the Bahamas due to their fake marriage. I now she you think that California might accept them as being legally married which has nothing to do with the Bahama residency permit. Stenr clearly said on the stand in court that they were not legally married.
If you are referring to civil unions, they're not legal in California. That stunt that Mayor Newsome (aka Major Nuisance) pulled in SF a few years ago was against state law.