well you're FISH in the tank will soon have ich since you didnt listen to the advise about not putting anything else in your tank. Just b/c you cant see it right now, if it was there before and you didnt wait, its still there. Just a matter of time, so when those damsels get ich and die, do not buy anymore fish until you wait for the parasite to die. Im not sure how long it takes for ich to die off but someone can help you out w/ that.
The only reason your shrimp havent died is b/c they cant get ich. Only fish can.
Your ammonia levels should be 0. You're tank is either not done cycling or whatever died in your tank caused this ammonia spike.
You really do more research before you just see something you have no idea what it is, and then put in your tank.
Whoever told you that ammonia levels werent important have shi* for brains. Ammonia is very toxic in your aquarium.
Im by no means an expert but i know that i studied months and months before i attempted my tank. Im not moving slowly but surely to avoid the kinds of problems you have. Until you slow down your problems will continue.
DO NOT ADD ANYTHING ELSE TO YOUR TANK UNTIL YOU KNOW WHAT YOU ARE DOING!