I actually worked directly on the SFC version only once, years ago. I think that could still be sorta done, but not without huge optimizations, like palette reorganization and better VRAM management. For example, injecting the improved battle backgrounds would required a massive palette search algorithm in order to compress 8 bit pictures to use no more than two palettes.
I do know more or less how the SFC code works, since it's what I use in IDA to decipher what the PSX counterpart does, but writing optimized code for the 65c816 definitively isn't my field of knowledge.
