The files here create new texture IDs for a specific race. As an example, I could put a hello kitty t-shirt on a froglok, change his skin tone to pink, and make his head transparent, but it would only appear if your illusion spell referred to that new texture/race combo.
Illusion spells have to be linked to a specific race and texture ID, so that change would require a brand new spell ID to be created. Not challenging in its own right, but outside the scope of the work here. You could try the forum for gear suggestions.