Azula is voiced by Grey DeLisle (Or Grey Griffin, depending when you ask her. It's very hard to piece together which she prefers, but it was Grey DeLisle in the ATLA credits.)
Wesley is voiced and acted by Alexis Denisof, who is an American from Maryland and yet both of the roles I know him from feature him playing an Englishman.
I use Bre Blair from the 1995 Babysitter's Club movie as her PB, because it was the closest match I could find to the book covers... but the voice on her is all wrong
Except for singing, but I consider his singing to be non-diagetic, he is NOT a good singer in-universe.