Blue and Black death feigning beetles are 100% safe from harm when kept with Hadrurus arizonensis I know and they clean up after the scorp quite well, mine lived with an adult male H. arizonensis for over a year and were fine. Also springtails are good with Tarantulas and scorpions that live in damp enclosures or even drier enclosures provided a corner or side is kept wet.
I believe zebra pill bugs (armadillidium maculatum) are a species of isopod that prefer a little drier climate than other isopods, but that is all I can think of. It would be awesome to see them in with a T or scorp since they are gorgeous Most clean up crews (especially isopods) have gills and breathe through moisture in the substrate, so it's difficult in a drier climate. Other than death feigning beetles that work with limited species, the best bet is keep a corner wet like @dragonfire1577 was saying and they can thrive like that.