This is a list of adult MPs who legally changed their names before they vanished. Women who changed their names because they got married or divorced don’t count. I decided children didn’t count either.
Peter Strother Madison (was Peter Scott Gruesbeck)
Neo Babson Maximus (was Charles M. Allen Jr.)
Frank Nash (was Asselin Nash)
Mikalena Nau (was Michelle Nau)
Jessie Shawn Mixon (was Robert Shawn Otis)
This is a really short list but I thought it a worthy topic anyway.
Fun fact: Michael legally changed his name after he turned 18. He has two middle names, and started life as Michael Robert David. Then he changed it to Michael David Robert — simply because he could, for no other reason.