Until now I haven't had the same companion on more than one character. It looks like rapport and possibly some outfit and/or mount customization is per character. I've had Ember on my main character for close to a year, I just did the companion quest to get Ember on a lower level character.
Am I wrong in assuming that the companion's build and XP level are account wide?
I can see that the XP and equipment on Ember that I got today is the same as my main's Ember. Am I missing something that will allow me to have different builds per character with the "same" Ember? At the very least it seems this would be something that the armory station should include.