in 3rd phantom yoruichi will train you as in whichever twin u picked at the start at a certain point in story (im playin now so ill re edit this then) several characters will have little black swords on their pictures during free time complete them successfully then later when suzunami along with the opposite twin attacks soul society i think for the 3rd time in a cut scene the one u picked will go bankai however if u failed even 1 training session the twin will use shunko instead. now back to ur original question No only the twin u picked at the beginning will be able to use bankai during the Tower so if u chose Matsuri failed the training then beat the main game her bankai makes her look like a dragon or rather a part of her has a dragon and regardless of what type she was while in Banka