regarding sitting on that pad in the last picture. It's a white cushion and if his diaper leaked it would stain the cushion and would be embarrassing so the dark cushion is used to hide that potential leak.
The last shot is incorrect. I watched that clip and he pulls up on his coat and those suit sides came up as normal. He wears a large suit-coat to cover his fat and diaper/girdle combination. The coat flaps out to the side due to the split in the back.
cheeto does however stand on ramps behind lecterns more often than not. Keeps him upright and not falling forward.