Another writing tip for the middle of the night:

Make your characters different by using the four humours. Or, if it's easier, just think of the Teenage Mutant Ninja Turtles.

It's basic stuff, but it works. A lot of all-ages entertainment gets written off too easily for what it can teach us. You don't have to follow it rigidly, but there's a reason these stories work. There's a reason the TMNT stick around. They have a dynamic that most any writer can work with.