I could totally see Cheese as Meatwad, although I also agree that Meatwad is smarter then Cheese, but that's not really saying much
. But I honstly think Mac would fit Frylock better more so then Wilt.
Only because Mac has more of a reasonable head on his shoulders, where Wilt is too indecisive. I think Mac handles Bloo and the Foster's gang much like how Frylock tries to handle Shake and Meatwad (with similar results to boot).
The only big difference between Bloo and Shake is the of course the adult stuff and swearing and what not. But the funny thing is, much like Shake, Bloo's probably done more stupid and insensitive things then he has good things.
Shake of course has done ZERO good things but still.