Hi! I was wondering if all of Olaf's fake names in the series refer to the fact that he's in disguise. Captain Sham is obvious, "Shirley you can't be serious" is an old joke, and Coach Genghis seems like it would be finished as Genghis Khan (Con.) Detective Dupin would presumably be "dupe," but then I couldn't figure out if Stephano, Mattathias, and Gunther had any joke like that tied in.
Stephano is an allusion to Shakespeare’s “The Tempest” (because the Prospero appears in the same book). Gunther is a stereotypically German name Olaf uses because he’s playing a foreigner. Genghis Khan was a Mongol, which is supposed to show how sloppy the disguise is because Olaf is clearly impersonating a Sikh and Mongolia has almost nothing to do with Sikhism. Dupin is an allusion to Detective Dupin from Poe’s “Double Murder in the Rue Morgue”, the first crime novel. Sham and Shirley are indeed puns on the topic of sincerity. Handler does that again later with Frank and Ernest (Frank and Earnest). Mattathias is an allusion to the biblical character, a high priest of Judaism mentioned in the Old Testament. Because Mattathias is never seen and obeyed without question, the religious subtext is quite astute.
I don’t think there’s a common theme to Olaf’s aliases, Handler just seems to pick what he likes depending on the occasion.