What should I do if I am marrying a Sunni girl who respects and understands the Ahlul Bait, and her Sunni community is requesting their own Alim to officiate the Nikah?
Sunni Shaikh can recite the Nikah because it is after all a Nikah contract recited by either Shia or Sunni or any one who knows Arabic properly.
The main point is to be sure that she will remain in the future respecting Ahlul Bayt (AS) and will teach your children the teachings of Ahlul Bayt (AS). You are responsible about the future if your children.
Wassalam.