You know when your own cast of characters becomes too tough to track that something is wrong and someone (or several someones) have got to go. 

So I killed off a pair of moms in my current WIP. The adopted mom and the birth mom. Which left me with a group of people weighing heavily on the side of testosterone which meant changing the mentor type character from a man to woman just to get a wee bit of the female viewpoint in her (though she is far from a girly girly). 

I’m sure this will add an entirely new set of problems to the plaot for my main character but it pretty much rules out the mentor being played by Danny Glover in the movie.