Getting this together was definitely at the limits of what I am capable of, but I did get it working. First thing is that I used Kyle McDonald's ofxCv addon
With this, I used the (much simpler) contour tracking to get the shapes, created shader fbos for each shape, and assigned videos to those as an alpha mask. I apologize if this isn't in detail, it has been a while and I haven't touched ofxCv since. If you need help with it though, get ahold of me and I'll share what I have.