I'm kind of lost here, some people say that I need to have a script to change the textures on the model, some say that I need to rapidly change the model itself, and some say it's in the model itself. What do I do??

can't really tell you much about this stuff, but that'd be on the model.

when you look at animated nifs in nifskope, you'll see there's controller managers and controller sequences etc, defining animations

and you'd somehow chain these together with the textures, if anyhow, i figure.

anyway, nifskope'll be usefull for you to start somewhere, and that's pretty much all i can tell you here

I know the basics of nifskope, but I still wouldn't know how to do that..