AEFW = acro eating flatworms. Usually the red ones are easier to get rid of. I've never dealt with white ones. Wrasses that are with caution will usually eat reef inverts like shrimp and snails.
You need to run a reactor or canister filter with carbon for the chemical treatments. If you're not able to do that, I wouldn't do it. Flatworms reproduce really fast. If you count on a single fish to take care of an infestation, you're being overly optimistic.
It's not a red one like most people have issues with. I lost a LOT of fish in a treatment gone wrong when Flatworm eXit was relatively new - and I had a huge infestation of red ones.
You could try PraziPro. Less hazardous than Flatworm eXit.
I agree, try PraziPro, it will take care of polyclad flatworms and is reef safe. I had some big ones, about quarter size, brown and white/clear and after the prazi have not seen one.