If you have another container, supplies, time, etc., then hatching brine, won't hurt; but your fish are in hypo and you definitely don't want to hatch brine in the Hospital tank for water quality issues. If you want to try a wiggling food to entice, you could pick up a very small amount of live black worms or live brine from an LFS. Of course adding anything else is also a potential to add something undesirable to the current equation. Bottom line, they need to eat and sooner is better then later, err on the side of them eating.
Rinse the pad, the hospital does not have a functional bio filter anyway. Water changes are going to be required as brute force "filtration".
Check your waterchange water for pH, ammonia, etc., as well. Always good to know the starting point. With all the changes of late, what is the current fresh water source?
IMHO: snails, shrimp, etc., would be as likely to show toxicity as the clowns if not more so.
There are a million things that could be going on but this is what we know for certain:
1. visible spots have been seen
2. elevated gill activity
3. sedentary behavior
4. lack of appetite
In my humble opinion, treat for ick until that is eliminated. Assuming the water itself is "safe"; stopping the ick cycle and getting them eating are the focal points.
