This strip is not really about the Mouse being a prophet, it's more about him being a smartypants. Saying "I know" after someone tells you "you're welcome" is kinda messed up. I do it all the time, it's fun!
As for the Cat eating the corndog, it's not suppose to be gross or adult themed. I don't know what you were thinking, actually I think I do, get your mind out of the gutter! Have you ever seen a kid eat something with a sauce or some kind of seasoning? They don't eat it. They just lick the seasoning, slobbering all over their food. I've seen kids at amusement parks lick churros clean, and actually it is a bit gross! The Cat puts pepper on his corndog for story purposes, how else would the Mouse sneeze? In old cartoons, pepper causes sneezing, and is used all the time. I haven't seen any pepper sneezing gags in any recent cartoon, maybe pepper from the 1940's was different from the pepper used today and once caused chronic sniffles. That's probably why I've never ever seen anyone sneeze from pepper in real life.