Strong fire slashers like King Mont, Oelde, or Rain works best here, but most damage dealers that uses slash works just fine. King Mont is the ideal one since he's also part of the "Large" boost.
Tidus is an easy recommendation since he's a free character that most players have, but might need Illusory Bell to be able to keep dealing high damage.
You can get Avian killers from espers and VC like Odin and Zuu. Otherwise, go with attack or slash increase espers/VCs.
Mini Dragon
Most slash or pierce units will work just fine. Both 2B and 9S can do slash and pierce, and they are part of the "Large" boost. Ahlim is a good cheaper alternative, or Owe if you EX upgraded him.