No. He won't be considered. The MYMU is for TRUE immobile mages aka mages that will burst you on their standard build path. Cho will not do this unless fed, but so will anyone lol.
Brand will 100-0 someone if he pulls his full combo off with only 2 or 3 items (maybe not even). True mage.
Zyra COULD 100-0 someone if she got her full combo off. True mage.
Vel'Koz will 100-0 someone if he lands all his skills and finishing with a disintegrating ult. True mage.
Cho is considered an AP tank and he's also melee. All mages are ranged. So if they count him, he'll be one of the last on the list.