Flashers are pretty and hardy, but tend to be a bit shorter lived than fairy wrasses. Not sure if its actual lifespan, age they are collected or what, but its been observed as well by people way more into wrasses than I am. That said, fairys and flashers can coexist together and rarely harass one another. Fairys can have a "complex" relationship with one another. I would highly suggest reading
this article about what ones can and cant go together in the long term. Ideally, three fairy wrasses would be ideal, so there is enough individuals to spread out any aggression that occurs, while also giving you enough individuals so that the wrasses 'flash' and display for you to enjoy.
If it were up to me, I'd pick three wrasses (either flashers or fairys) and just run with that. I have an
C. exquisitus,
C. cf cyanopleura &
C. rubeus in my tank. They display when the daylights go off and I have an hour or so of actinics for 'dusk' lighting. Flashers have a similar behavior and can actually change colors when they flash - so they are quite breath taking as well. Neither genus buries in the sand, instead they make mucus cocoons while hiding in the rockwork at night.