All this talk about Blaine being Ienzo or Braig, when in reality, he is... both! BRAINE (L=R because japanese) -> BRAIg + iENzo. Blaine will fuse with a guy called Gizo, or Zigo and will defuse into Braig and Ienzo! Based on the visual clues, this Gizo is young, has Braig's hairstyle, blue hair, and probably a pirate. You heard here first!
Back to being serious. As much as I would love Ava's return, I doubt she is under that hood. Nomura obviously wants to play the mysterious traitor card again with the new leaders. Since Ava met all of them, she could point out the one taking over Strelitzia's spot in a second, killing the mistery of the traitor. My guesses: it's either Larxene (since she has a connection with Lauriam), a somehow surviving Strelitzia, out for revenge, but not knowing who struck her down, thus the coat to spy on the leadrs, or a new character who wants revenge for Strelitzia, symbolisied by the flower.
Back to being serious. As much as I would love Ava's return, I doubt she is under that hood. Nomura obviously wants to play the mysterious traitor card again with the new leaders. Since Ava met all of them, she could point out the one taking over Strelitzia's spot in a second, killing the mistery of the traitor. My guesses: it's either Larxene (since she has a connection with Lauriam), a somehow surviving Strelitzia, out for revenge, but not knowing who struck her down, thus the coat to spy on the leadrs, or a new character who wants revenge for Strelitzia, symbolisied by the flower.