Without any clear indicators other than scratching or flashing, I also suggest a treatment of PraziPro for a possible case of flukes. There are methods to diagnose a fluke infestation, however require removal of the fish from your display tank.
I also agree cleaner shrimp and wrasses will not be effective on controlling these infestations (flukes, ich, etc.). Cleaner shrimp are interesting additions never the less if you stocking allows. I would leave the wrasses out of your tank given they need a few large fish to thrive and are better left in the ocean than in most people's tanks. Money is better spent on acquiring some QT methods and control it before.