I will add to this, the patch that I have essentially removes ALL the other game's data, if I'm remembering correctly. Obviously there's still some there, but I removed all the other graphics that I could find that weren't SMB2 related.
It's definitely possible with the others and not terribly difficult, but I'm not willing to put my time into it. SMB2 was the only one that I wanted to work with out of the bunch.
Though, I think this patch does have some bugs in it, fairly certain anyway. I never actually fully played through to test, I just kind of did a first couple levels run and let that be it.