If its eating, then you've already more than halfway there. Usually the biggest obstacle with wrasses are getting them collected/shipped ok (which you've apparently avoided) and getting them to eat. After that, flukes are the next most common issue, but that can be easily taken care of with a couple of PraziPro treatments. Then its just a matter or replacing your snails every 8-12 months as they succumb to the wrasses appetite

I've got five or so in my tank (flashers and leopards) and they are hardy once established. Last thing to keep in mind is if you want to add another flasher into the tank later on, you may need to invest in an acclimation box so the newcomer isnt bullied. This varies in intensity depending on the wrasse being introduced. I agree - reading up on
@evolved articles on wrasses is a wealth of general information about keeping wrasses as well as some species specific information.