Take all fish out and pop them into a hospital tank. Just set it up and don't worry about the cycle process so much. They won't be there THAT long anyway...
Ich inside your main tank will die in 1 day without a host and if your temp is at around 72+. And 1 day is like being on the safe side already, they die much sooner than 24 hours actually. Not that this 1 day w/o a host thing matters anyway, because treating the fish will take longer than a day...
ANYWAY, so move your fish into a hospital tank. Set it up and get some chemical meds because these work much faster then salt + heat. Your fish should be cured within 3-4 days, I tend to wait till day 5 before officially calling it. At this point, just scoop your fish out and pop them back into the main tank.
I have done this before when I had boraras urophthalmoides in my CPO tank. I bought some boraras and they ended up having ich. I didn't want to treat my CPO tank so I moved all 16 of my boraras out into a newly set up tank, new filter, and a heater, no substrate or anything. Just water and sponge filter and some medication.
By day 5, I popped them back into the tank nice and healthy and didn't lose a single CPO.
- note -
I did no water changes in the hospital tank. Didn't need to, just don't feed much. I think I only fed them micro-worms at the time so that really wasn't much waste. Only fed them once every 2 days too, so I only fed them a total of two times while in the hospital tank.
Make sure you inspect your fish before adding them back into the tank. Just to be sure there's no more ich on them.
Ich won't host on inverts so you should be okay.
