Just personal preferences/experience. I tried to keep shellies with my some of my calvus in the past, but things didn't go too well for me.
My dominated male yellow calvus got curious about my gold ocellatus pair and decided to check them out. The male ocellatus started guarding his shell and nipped my calvus a few times. Guessed my calvus got fed up, and just engulfed the ocellatus male. Spat him him out minutes after all tattered up.
After that experience I just kept my shellies in separate species only setups. Easier to collect their babies this way too
You can try housing them together, but I just thought I give you a heads up. I do know some hobbyist who have successfully housed them with other tangs with no problems though. Maybe just a little bit of bad luck on my part.
Another issue I ran into was the shellies not being able to compete with my larger tangs for food.
See that's why I was hoping to find a shell dweller that acts like multies but gets bigger. So the comps can't take an adult down