He didn't eat them unless they were incredibly small. A mystery wrasse might kill them but his belly would be huge and there would be a mess. Now he could have killed them and if you have a lot of clean up crew a small dead fish can go away pretty quickly. It's rare for a fish to just completely swallow another fish in our tanks unless you've got something like a lionfish or grouper in there. If they aren't in the overflow they may have gotten beaten to death by him. Also the other post was correct about the shrimp, if it isn't a really big shrimp he'll eventually give it a taste. I've gone through a couple cleaners and even my huge blood shrimp got a couple antennas taken off when the wrasse decided to give him a taste.