Well Phoenix Wright is a weird character in UMvC3. He has three different modes, based on what mode he's in. There's investigation, courtroom, and then turnabout, which has a prerequisite before activating. I was thinking something along the lines of the mix of him and the ice climbers, where each twin has a different health bar, but since they're two characters, they each have smaller health bars then other characters. it would require a quick button combo press, and you'd switch into the other twin. Hitting a set of prerequisites would then activate "Twin Terror Mode" where each of them appear on screen at the same time and share a health bar, and have more powerful attacks.