How old is Cat? In "The Big Dog Problem" he states that he is no longer a kitten, but then states that he is still growing.
Judging by "Peg Meets Cat", he's three. That's an adult for a cat, isn't it?
Does Peg ever really need to count backwards from five? She seems to have already stopped freaking out by the time Cat does his Get A Hold Of Yourself Woman gesture.
It's possible that she only sounds calm and the point of counting backwards from 5 is to keep from freaking out more, however, they show her counting backwards from five to really teach the viewers (little kids) a way to calm down when they're upset.
The elephant in the room: How are all these historical people alive?
Maybe Peg and Cat brought these people back by either a time machine, or living in the same universe as Clone High?