For the identification, I like the idea of differing sigils used by each kingdom. 

I also like the idea of the owl, but my personal touch would be to have it clutching an apple in one foot and a scroll in the other. Symbolizing both knowledge and wisdom. Or I guess it's be wisdom twice, since that's the symbolism of the owl too.

For the Allegiance, I'm picturing a lions head (symbolizing nobility and courage) with a waraxe and a pick crossing above (symbolizing both their skill at war and their determination and willingness to work for a living)

For the Exiled, I feel like a raven would be a good choice with how it tends to be regarded as an ill omen and a symbol of cruelty and treachery. It could be clutching a few arrows in one foot and a small hand mirror in the other (a symbol of their affinity for hit and run and guerilla warfare, and a nod to the method of the betrayal).

As indentification, they could be used on banners and soldiers tunics as a coat of arms, and on signet rings by the royalty and their trusted advisors.