Anima is female. The gender of Aeons is the same as that of their Fayth, which is why Valefor is also Female. (Her fayth is a little girl)

Also your description of Ultima is off. She is the High Seraph, the angel who rebelled against her creators, but failed in her attempt.

My favorite summons are Alexander, Shiva, and Carbuncle (so cute ).