It looks like you're doing this in edit mode. In which case, this script (it's not free though) might be what you're looking for- it's the only one like it I've seen: https://blendermarket.com/products/accent-pro-edit-mode-layers

Otherwise, you can edit it without if you very carefully select faces you want to apply a material or paint, invert the selection, and use "H" to hide the selection you don't want to paint.

As far as key-framing the textures to change, unless someone answers it first, I'll look into that...