Joe Rockhead has quite a large part in this episode, implying we'd see a lot more of him in future episodes. However, he's used very infrequently for the rest of series. He shows up in "Impractical Joker", "Fred's Birthday Party" (voiced by Howard Morris rather than John Stephenson) and, unnamed but evident in appearance and voice in one of the last episodes, "Curtain Call in Bedrock."
One of the other Lodge guys is Charlie.
Joe mentions Fred's uncle in Texas, who has not yet made an appearance.
Joe Rockhead is a member of the Lodge and his wife's name is Rita.
This episode was recorded on 5-20-61.
The term Grand Poobah alluded to the character of Pooh Bah in Gilbert and Sullivan's The Mikado.
In the operetta The Mikado, Pooh Bah is a haughty and pretentious character who holds numerous high offices to the point of often including "Lord High Everything Else" as the last one on the list. The name became a mocking title for those self-important individuals who with inflated sense of self.