Esha Exit didn't work...? Is this ich?

Despite repeated doses with Esha Exit and 2000 my goldfish still seem to have a problem with ich or something like it. I stripped the tank bare and scraped off the white capsules from every surface I could under running tap water. The tank no longer has any decorations in it, only filters. 2 weeks later there is one of those little cyst capsules visible again.

But the symptoms are different from what I expected for ich. There is no sprinkling of grains of salt all over them. Not all the fish are affected. I'm seeing one or two isolated little spots on the fins of certain fish, a couple of the spots near the edge of the tail fin eventually developing a trailing spiderweb-like filament, about 1cm long, and later the same day the spot will be gone but a tiny little hole/tear left in its place. The tear disappears within a day or two. One has been quarantined and yesterday developed a single white spot right on top of its head, slightly raised almost like acne. This same fish also came up with severely shredded fins in a matter of hours, hence the quarantine (it responded very well to treatment for fin rot/melafix).

The cyst capsules on the solid surfaces of the tank seem consistent with ich. But it isn't responding to Esha Exit, heat or water changes and the spots themselves just look different from ich cases I've seen before. I can't use salt because one of the fish had a violent reaction to it before, nearly dying.

Is this something else? Any ideas for treatment?