A few pointers:
Yes - all exposed fish need to be treated for flukes. Some flukes are more host-specific than others, but you cannot really tell. I'm not 100% convinced that you have flukes - grammas do get flukes a LOT, but they will give symptoms prior to death; pale color, scratching, hiding and not eating.
FW dips only screen for one species of fluke, Neobenedenia. The others are too small to be seen without a microscope, and then, they end up so contorted from the dip that it takes a lot of experience to ID them.
Wrasses have high oxygen requirements, they do not always do well with prazi that has been dissolved in a solvent - better to use the powdered prazi formulations with them.
I used to think that worms would be killed by prazi, since it "kills" worm parasites - right? Turns out, prazi just stuns worms and causes the parasitic ones to drop off of the fish. Same thing with feather dusters, they just get stunned.
You'll need to run your skimmer for proper gas exchange, just don't collect the skimmate during the treatment.
Coral loss is rare after a properly done prazi treatment, but don't let the prazi powder settle on delicate corals. I have heard of coral losses, but in viewing those cases, the corals were not in good shape going into the treatment.