I have. I mix all kinds of wrasses. I just don't get 2 males of the same fairy/flasher in a tank under, say... 180G, or so? I have had multiple leopard males with no issues.
I had a mystery, male rhomb, 2 male flames and a half of a dozen leopards all with no issues. I have heard that mystery wrasses can become aholes if they are overcrowded or underfed, but I experienced no aggression from mine.
I have no idea how you tell a female from a male mystery. Probably a blood test.