This is a wonderful fan art I found that I like to refer to as the Gundam Kagekidan. I absolutely love it! ...then again Sakura Taisen is probably my favorite "mecha anime"/game series ever. Though I use the term "mecha anime" loosely. I find it tremendous to see characters from Gundam dressed up as people from the Teikoku and Paris Kagekidans. However...
I still don't know who some of them are. By my estimations we have (from left to right) Chan from Char's Counterattack, then top we have ????, bottom is Puru Two, to her right left is Elle Vianno, to her right is Tiffa Adill? then is Christina Mackenzie, right of her is Amuro Ray, under him is Elpeo Puru, to her right is Rosamia Badam, above her is Sayla Mass, above her is Char Aznable, to the right of Sayla and Char is Roux Louka?, to her right is Beltorchika Irma and right most is the apparently shy (and undoubtedly tsundare) Haman Karn.
So I have no idea who the tall greenish black haired gal is, nor can I explain why an apparent Tiffa Adill is there if all the other characters are UC. Anyone have any ideas?