This seems like a good idea for a hack adding in all the features from the GBA version, but there's still plenty of things that need porting and updating. One minor thing I might mention is Yoshi's arms are still brown. One major would be no intro cutscene from the original. All of the best features should be ported to the SNES, however, I appreciate what you've accomplished so far.
The title screen seems like a downgrade though, it's best to leave it to the vanilla version to not take from the experience. Thanks