CPS3 was just CPS2 with a ton of extra RAM to cut down on load times from the CD and a couple more bells and whistles.
That system is ancient technology, the GBA may have a problem with it but in no way should the DS suffer anything at all. I mean, if it comes down to it just use the 3D engine. Most if not all PS1 2D fighters used 3D hardware acceleration, and it's also how the DC handled all of it's 2D fighters, including SF3. As I said before, the only real issue graphically would be the resolution which would mean bgs need to be resized and characters need to be redrawn.