Good, DLC sucked in Awakening!, the fact they had Priam and Chrom where they could tweak them both to make Ike, but noooo! Ike should have a generic model!
I think the design of the character doesn't change according to the Mirage, I think the Mirage only changes the weapon, and I have a feeling Weapon can promote. the design of the character depends on the class they are representing that's all.
Buying both,Nohr would be my first campaign, I used to be a Hoshido man myself but my favorite class is obviously the Hero class, and it looks glorious in the Nohr path, so that's why I choose it, it would be Hard not having Ryouma but I can manage.