In Japan she is named Miss Goldenweek, but there is no such holiday in America, so when 4Kidz translated they changed her name to Ms. April Fools Day. Thanks for your question!
Mr. 1! He chases down foes and locks them in place with good damage. Our favorite overall. Django is good for stuns, and Dr. Kureha is good for locking enemies in place with poison. Gedatz can be fun on maps just to launch enemies and break their combos.