Like most other wrasses they like to sleep under the sandbed. You'd really need to add that to keep them happy. In addition they can grow to about 12 inches, so your going to need a big tank for it. Overall I think another fish would be a better choice.
Yeah best to ask first! Lots of wrasses use the sand as protection and a quick escape. If they don't have it, they still try to dice but end up damaging their mouths and once that happens they won't eat
I think that's ok for a quarantine tank, but I wouldn't want to do that in the permanent home for the fish. It's just too small an area, and restricts the fish to one place in the tank, which it may not like.