That he does. The only snafu he had was with Coolio for Gangster’s Paradise. Apparently the label said yes but didn’t actually check with Coolio and he wasn’t happy about it. Weird Al apologized for the mixup and they made peace with it later. Weird Al said the only star that has consistently turned him down was Prince, who didn’t find the whole parody thing funny.
Yep that one is true as well. Paul is a vegetarian and didn’t want a song about non vegetarian food. He didn’t have a problem with parody in general, just that specific instance. Geez, I know way too much trivia about Weird Al :)
Edit: the song was created just never released.
https://en.wikipedia.org/wiki/Chicken_Pot_Pie