Would be fun to see have to admit it would be pretty hard to code tho.
As For one the cape Physics are weird I think you know what I'm talking about pull forward to speed up press backwards once to rise. Not to mention that You would Have to code the super jump and not being able to fly on the Koopa shell or well in your case on Yoshi with the Yoshi mod.
Also in the credits would Mario fly the same way or use the cape to fly as in how he flies in Mario world or Just Mario 64 end sequence flight With the cape flowing like in Mario world Promo Material and like the Super Koopas?