While we cant rule it out, a Rhalgr primal seems to be thematically a little too similar to Ramuh. I mean old guy in robes with beard and who is master of lighting. They even both have a staff as a weapon.

The WoL wouldn't empower a primal of the twelve though. Even if the WoL was a devout worshiper at this point I don't think they would see a Primal in the form of one of the Twelve as actually one of the Twelve. More likely they would see them as the imposter they were.