I don't think I would try to embroider on them, that is my own personal take though. If you are determined you could do the embroidery on something else cut it out and then glue it down. Somewhat of an applique style.

You can use regular stablizer on the back and washaway on the front and cross your fingers that the design doesn't 'fall out' after you've stitched it. This will sometimes happen on leather, plastic etc. But some cuties have had good luck with the leather so maybe that will help. Personally I'd stitch it on fabric them stitch it on like an applique....