If you absolutely must restart...
Having sampled all of the Tank jobs, and knowing all Au Ra are implicitly refugees, I would highly recommend MRD and Limsa by extension.
There is no canon background for the Warrior of Light beyond your opening snippets. However, as MRD/WAR is much more brutal in style, and the Xaela are nomads who likely do not have martial arts a la gladiator combat, MRD is much more suited to their culture. Furthermore given the plight of the Au Ra, any arrivals would have to be by ship; Ul'dah and Gridania have you arriving via carriage. Therefore, if you absolutely positively must start as a Xaela, doing a tank class, MRD is the way to go. (You'll probably definitely have to get GLD/PLD up so you can get Provoke, but I digress.)
I cannot vouch for how well their culture meshes with Limsan, but.
Alternatively you could start as an ARC, as Xaela are based on Hun-style Mongols and they were renowned for their archery. I'd suggest a mounted combat class, but those don't exist (and probably never will).
DRK is somewhat centered around Ishgardian culture (though the 30-50 line isn't - no spoilers!), so it doesn't really matter what class you start as if you transition to DRK after getting there. Tank classes still recommended for their cross-class skills, but.
Really, anywhere is fine. Xaela probably aren't well-versed in arcane arts so a magic class is unlikely, but all three city-states have reasonably close ports so regardless of what class you want to start as it's fine. You're asking for very specific information that doesn't exactly exist and continue to do so despite being given the best answer possible, much to the consternation of others.
Psychological disorders are no excuse. I have one too.