Billy = Adam DeVine (I low key think his persona is influenced by Billy, Adam Demamp seems drawn from him too, and they all share a derpy physicality I would say)
Mandy = Aubrey Plaza? Doesnt “look” like Mandy at first but April from Parks and Rec seems very Mandy
I don’t disagree with your reasoning, but both of them are in their forties.
When has that ever stopped actors from filling those credits?
It might not stop them, but sometimes it should.