Some general responses…
Dat had to perform a lot more often than the other comics. Audition, Round 1, Round 2, Comedy Showdown vs. Dave Mordal, Comedy Showdown vs. Geoff, Final Five, Results Show, Jay Leno.
Interspersed with this, they showed him practicing the jokes in his act. There’s no way the viewer would not see a repeat. Substitute your favorite comic doing his or her act 8 times in a row and think how funny it would be.
Comedy is about going up in front of a fresh audience and getting laughs, not about coming up with an act that you repeat over and over to the same people. It appeared that people were laughing at Dat’s jokes.
As for Dat doing martial arts, in his Results Show act, he said this was a situation that happened to him before he started practicing martial arts. Dat also says he is math challenged in a joke, yet he has a booklet with a lot of numbers and graphs. Again, this is the art of comedy. It’s based on personal experience, but exaggerations or outright lies are permitted. Do you think Tess really worked as an overweight stripper named “Tub of Love”? Are stage magicians supposed to be more honest about illusions designed to trick and fool the audience?