The thing is we don´t know if the "evolved" kagune is a powerup that comes from cannibalization or is a powerup that only eto can give because of her special nature.
Noro, Kanae, Kaneki and Eto are the only ghouls that showed this ability and they got only by having Eto do something to them (Noro and Kanae) or eating her already mutated kakuja (Kaneki), which points all out that is something that is (probably) only her can do, and regarding the mouths and eyes apparently you need to have some kind of intelligence to make the eyes appear unlike the mouths since only eto and kaneki manifest them,so i can kinda assume that even if Shikorae cannibalised like crazy, got the genetics necessary to mutate to kakuja (if he is Rio indeed then he is already past both of this steps kinda, isnce Rio got half Kakuka), and by one random reason of destiny developed this crazy ability he would not manifest eyes (dude is so dumb he looks stoned 24/7).