$20 a piece is a good deal, especially with Covid pricing. I know that my leopard wrasse is bulltproof. He survived a heater failure, a 15 degree temperature drop, a sperate electrocution event, and skyrocketing nitrates (this was in my wife's tank).
Leopard wrasse are sensitive and delicate. I would absolutely NOT buy one that isn't eating. They are also sensitive to quite a few medications, so quarantining is pretty difficult. Typically the most expensive fish you buy is one that dies on you right away. Typically if a LFS is not able to get them to eat then most hobbyist will struggle.
I just bought one about 2 months ago. I made sure she was eating at the LFS before I brought her home. The transition went extremely well and eats any frozen food I put in the tank.
I’m glad I made sure she was eating before I brought her home. Glad I went through with it. I will say I would not have made the purchase had I not seen her eat.
I've had a Leopard Wrasse for nearly 4 years and mine is also bullet proof. I've had a mini tank crash (because of a basement renovation) and it killed half of my fish inhabitants but no effect on my Leopard.
Once you get them to eat, they are a pretty bullet proof fish. Both of mine(melagris, and blue star) transitioned fairly easily, and are the most active fish in my tank.
The thing to look for in leopard wrasses is loss of mass in the dorsal musculature - in other words, pinching behind the head. I would have no problem buying one from LFS that did not eat (they can take a week or two to get the hang of frozen) but I would not buy one with pinching. It almost always means the fish is a goner.
I would be more worried about those fish being kept with no sand than them not eating. They can take a while to eat. If they used copper or hypo, then I would not buy them either.