how to put your own character over an animators character so you dont have to do your own rig

Disclamier this is completely for just fan remake purpose not to sell or plagiarize!
This is a screen shot from an animated series im kind of interested in. But i want to edit the scene. I dont want to have to do my own rigging for such a short scene. Id rather keep the rigging that was done in this animation but mask over the girl with a different character but one that moves accordingy when she moves. Kind of like when you can use a mask to hide something in a video and make it continue to hide at the right moments depending on where it moves during slides, or is there no way to keep the rigging that was already created by a different animator and just mask their character with your own?
Will I have to just re rig that scene with my own character instead of relying on their rig?
