Sugi, welcome to Tropical Fish Keeping forum. Glad you joined us.
As Barb said, a 5g is much too small for any of the fish mentioned. There are suitable fish for a 5g but zebra Danio is not one of them, it needs at least 20g. But before we get into possible small fish, let's get the ich cleared up. The fish that survive, if any do, will have to be dealt with first.
I know it is thought that starting with a small tank to "get the feel" of fish seems fine, but in fact it is always better to start with a larger tank. The larger the tank, the more stable the water will be, not subject to sudden fluctuations. And more space is always better for the fish whatever they are. Many start with small tanks, lose fish repeatedly, then give up. Please don't; it is really easy to have a healthy aquarium, it just takes some understanding and careful research. Never rush into something, impulse buying of fish, whatever. Plan it well beforehand.
Something to help us suggest suitable small fish would be knowing your tap water parameters. Hardness and pH is important. You can find the hardness value from your water supply folks, and possibly pH. But a liquid test kit for pH is a good investment as pH is something you should check periodically. An API "Master" kit contains tests for pH, ammonia, nitrite and nitrate; these are the basic tests. This kit would be a good investment.