Red does not have the finesse needed to hold several of those things in his mouth the way Green has learned to do. This is just Red and Green making funny faces at each other with minimal dialogue.

Most of the time these characters are drawn with black dots for eyes, and that is what their eyes actually look like. When they have circles for eyes it doesn’t mean that their eyes look like that. It’s just to show expression. The characters with large eyes that have a different color are actually that shape and color. It is interesting to note that has eyes like a Grumble even though he speaks like someone from Oversea. That just means he is ethnically a Grumble but grew up in Oversea so he has that accent.