I'm not sure about the Tusq saddle.
To stain the neck, you would need to sand off all of the Taylor UV-cured finish. Otherwise the stain will not penetrate into the wood. Without removing the neck, that will be problematic at the heel where the neck joins the body. Once you've sanded down to the bare mahogany, then you could apply stain. Then you'll need to apply pore filler to get a smooth surface on the mahogany. Then, finally, several coats of a clear topcoat (sanding in between coats) such as polyurethane varnish. And all of this must be done without touching the fretboard binding.
That's a great deal of work just to change the color.