...I've also gotten the idea that Alistair naming my Tabris the Bann of the Alienage may run into similar problems as you described above. The Chantry and the nobility are likely to resist when she insists that the guards have to be elven, and that they will have the authority to keep non-elves out. And from the other side, there are going to be people in the Alienage who still blame her for Howe's purges, and who worry that the change in the treatment of their people is only going to last as long as F!Tabris is the King's mistress.
Because I've totally been thinking about this...