He's definitely been hoarding secrets about the Cishaurim! Gosh, I really hadn't thought about if Meppa is not a special Cishaurim. Leave it to Bakker to be able to insinuate some kind of interpretation that blinded the reader to the truth!
I can't remember, did the meaning of # of snakes ever get figured out? I think Moeghus had 3 when he spoke with Xerius, 2 when he talked to Kellhus, but the Cishaurim at Mengedda had 5 each?