Mike Myler
Have you been to LevelUp5E.com yet?
....?Adept (Exalted Athlete)/ Rogue (Ninja)/ +Artificer (Machinist) for Donatello, Berserker (Rager) for Raphael, Marshall or O5e's Fighter (Samurai) for Leonardo. Hmm...if Samurai was an A5e subclass, would it be a Fighter subclass or a Marshall subclass? As for Mikey, you might be right. None of the A5e subclasses scream Mikey! What about one of the O5e subclasses for him?