Any name changes (including adding a middle name or initial) result in the loss of assigned seats.
XX seat messages do not travel from SHARES (US Airways system) unless an action on a segment is taken. Name changes and/or seat assignment cancels will not generate a XX message from US to your OA System.
Choice Seats are mostly window and aisle seats toward the front of Coach. Buy Choice Seats on all US Airways and US Airways Express flights during booking or anytime after.