About the Wake of Madness. Won't the Colossal-sized 'footprint' of the creature itself completely overlay the Gargantuan-sized mob? Or is that entirely the point? The mob swarms opponents, then the Momeh cherrypicks them from above...
Basically, yup ;)
So in reality players have to face the mob damage plus the Charisma damage, all the while the Momeh is attacking from above.