There is a book adaptation of this episode called "Pick A Dad-Any Dad!", but with many differences, such as the ending part being that Timmy ends up going to the festival with his dad afterall, instead of his mom like in the show.
Sanjay's Stepdad is not good at math as he stated so himself. If he doesn't know what number comes after another number, he has to start over at the beginning.
Who's Your Daddy? - The title is a reference to the famous phrase.
Who gets up at 5:00 (am)?- Timmy's line is a reference to the wake up time for the U.S. Army Boot Camp.
Cosmo flashing back to him being a scout troop while he notes that it was like it was only yesterday.
When the flashback is showing Cosmo trying to help an old lady to earn a badge, the old lady gets hurt or injured in a somewhat violent but comedic fashion.
Mrs. Turner says she would be doing something with her 397 Cream Puff Merit Badges, but if you count the number of badges there are actually only 289 badges not 397.