I haven't solved any of your riddles, but I did discover that "conundrum" has an interesting etymology.

conundrum .
16th-c. Oxford University L slang for pedant, whim, etc.; early sp. quonundrum
1 a riddle whose answer contains a pun (Ex.: “What‘s the difference between a jeweler and a jailer?” “One sells watches and the other watches cells.”)
2 any puzzling question or problem