Not all wrasses need a sand bed. The only one I know of is the Leopard Wrasse. Mine also dive bombs into the sand. I actually rarely see her do it. You just see a puff of sand. I do not recommend this fish for a bare sand bed. They are all wild caught as well. One funny thing I noticed about mine was her sleeping habits where not on this time zone. After a month or so she started sleeping at 10pm and waking up late morning (lazy fish..haha). She sleeps at the same time every night......amazing internal clock.
My wrasse could care less about the other fish. I do see her hunting for pods alot (also eats, pellets, rods, flake) so an established aquarium may be best. I may have gotten lucky as I have heard of others that wont touch pellets, frozen or flake.