If you wish to revist this concept of Toddler Mutant Ninja Turtles, I suggest you portray their unique personality traits at their early age:
Leo: leadership, most dedicated to ninjutsu training
Raph: aggressive vigilante
Mikey: carefree, creative, pizza connoisseur
Donnie: innate genius
Otherwise, this work looks good. Notably, you portray Splinter as the father figure well here.