Hi Tack!
I'm so happy to have helped you starting your adventure! The asset works at its full potential when used on softwares like Unity, GMS2 etc, so some of its features are cut off due to the RPGM MV requirements!
For the character generator, you should modify the scripts of the software to have each part working into it, otherwise you need to use an art software, even a simple one like Piskel!
Have a nice game-making :)