Azem doesn't have to look like Ardbert in every reflection. Matoya's shard on the First is that of a Nu mou (Beq Lugg) and Cid's shard is Chai-Nuzz, a Miqo'te.

Golbez's physical appearance is irrelevant. His face probably wasn't shown just because of technical limitations, as they didn't want to spend resources on modeling a unique face there.