I agree with you about Master Splinter being Raticate, but Shredder should be Scizor since Scizor is made of steel (like Shredder's armour). Krang should be Ditto, but only in terms of its physical appearance and not in terms of its ability to transform into every other pokémon. Bebop should be Chaobu and I agree that Rocksteady should be Rhydon. I also agree that April O'Neil should be Misty (but called 'Misty O'Neil' in terms of her full name) because it makes sense since Misty loves water-type pokémon.