You might be right. I've been wonder if there are two or more diseases going on too. The blue cleaner goby is always on the fairy wrasse picking something off. It was on the flasher wrasse cleaning as well before it died.Neurological issue could make sense perhaps but if the midas blenny keeps flashing.. could have more than one issue.
Most flukes do not show in a freshwater dip. I believe it is just 1 kind if my memory is intact.