I also recall hearing what sounded like Wilma and Betty exclaiming "Svengoolie?! EWWWWWWW!" Similar to a line from at least one original episode ("In the Dough"). Or maybe they were other characters...
At the end of Saturday’s show there was a rather long clip that sounded like the Warners applauding. I’ll have to try and find it again for a transcript and source. There was also what sounded like Sylvester saying “Aah, shaddap!” but that could be from one of many, many shorts.
I've also noticed dialogue from The Three Stooges' Disorder in the Court ("Siddown!" "I'm a victim of soicumstance!" "I'll squeeze the cider out of your Adam's apple!"); a certain clip from that short was shown during Tarantula.
I think I kno why Nicktoons brought back older shows, as well as NickRewind, I think it might have something to do with Tooned In. Tooned In is a trivia game show with Nickelodeon cartoons trivia questions.
Ricky Roxburgh, one of the writers for Monsters At Work, said how he isn't thrilled that the show didn't get mentioned that much in the article. He compares the situation to that of Tangled The Series (which he also worked on).