Oh boy... First of all...
Welcome Aboard, Matey!
Now let's start getting to the thick of it. Take no offense, but I'm going to list the things most of us would consider wrong so that we can then discuss how we might be able to correct them. I think with my level of experience, I'll need others to chime in to confirm or deny some of my suggestions, so don't act solely on my response.
Cycling tanks with fish is pretty much a bad idea for most of us here because it is stressful on the fish and even if it survives its lifespan has probably been cut short. When you are cycling a tank, you're going through the progressions of cultivating beneficial bacteria that converts Ammonia into Nitrites, and then the same from Nitrites into Nitrates, which then are consumed by Alga and micro organisms. Ammonia is the worst of the three for your fish. Cycling a tank with a fish is like asking a person to step into a gas chamber and breath in the bad air until only good air remains. I would avoid doing this ever agin and let a tank cycle with something like a raw deli shrimp.
Next... 1 1/2 months (2 month old take, going back 2 weeks when you added more) is a little too early for that many fish in such a new system, especially one so small. It wasn't that bad, but time was cut a tiny bit short. The best thing you can do for your tank is be patient. Very, very patient. Did I mention, patient? There are many things happening in a tank that we don't see. That beneficial bacteria that is consuming Ammonia isn't like a light switch where it is either on or off. It has more of a dimmer switch, where it gradually gets stronger based on the bio load. The larger the bio load, the more of that bacteria there is to consume/convert the Ammonia. If you dump in too much too soon, you run the risk of Ammonia spiking again, which is part of what you are experiencing now, but not solely for that reason. So what do you do from here on out when adding things? Wait a couple, or better several weeks between new livestock (fish, coral, invertebrates) additions. This will allow the beneficial bacteria to catch up to the bio load.
Curious, what were the new fish added? Whoa, wait... 5 fish? Within 2 months. Yeah... We need to slow down! Big time! 5 fish in a 2 month old 30 gallon tank is really bad. We really need to know what types of fish you have, and if you can even return any of them or maybe setup multiple QT/Hospital Tanks. I have a big hunch that your LFS is encouraging you to buy, buy, buy and saying that it will all be ok. If that is the case, they are not reliable at all and are giving you extremely horrible advice. If you doubt this comment by me, consider the undeniable truths that are right in front of us, your tank has sick fish.
So the number one thing that can cause a fish to get sick is stress. Most LFS treat their water with copper, which is masking any illnesses the fish may be hosting, making them look perfectly healthy when in truth they might have a little runny nose. When a fish is packed into a container, transported, and then thrown into a new environment (sometimes twice within a week), this is probably the most stressful thing that they can encounter short of that new environment being a shark tank. (Fish are friends, not food) It is extremely common for a fish to get sick after all that moving around, which is why a Quarantine Tank is strongly recommended. Do a little research on Quarantine Tanks to find out more, but the general idea is to put all new fish in the QT for a few weeks before moving them into a DT (Display Tank) so that way they don't infect the system, not just the other fish. Yes, your entire system is now infected (well maybe not now after the copper, but it was). Ick has several forms in its life cycle, and can live in a tank without any fish for several weeks.
As mentioned above, copper should not be used in the DT, only in a Hospital Tank. Part of the reason why your water parameters are all over the place is because you have killed small things that were living in the Live Rock, hence its name, Live Rock. There are more than just Algae and Bacteria... There are worms, micro organisms, isopods, copepods, maybe some bivalves, perhaps a shrimp, who knows? Point is, most of those things don't do well with copper and die. When they die, they rot and you get Ammonia. That's why your water smells funny... Death. You essentially have a 30 gallon pool of death with 5 fish struggling to survive. So what can you do now?
I honestly don't know the best course of action. Here is what I think I would do, but I would be researching like crazy to get the right answers... Don't do what I say here until others chime in and/or you have researched things further! I would toss the Live Rock, it has been soaking up copper that I don't want in my system. It could leach out later too, which is no good. Same with the sand. I would convert it into an empty tank with just the fish. I now consider it a Hospital Tank. I try hard to split the fish up into separate tanks, at least 2, maybe three, all of which are Hospital Tanks. If possible, I get the DT empty now and do a cleaning process I'll mention shortly, but it might be too many tanks. Next, I get new Live Rock and put it in a completely separate tank/container with a heater and powerhead to start cycling it (unless I am able to empty and clean the DT, then I do this step in the DT). I wait on the sand (unless I am in the DT with the Live Rock)... Once my fish have been through the Hospitalization for a long enough period, I empty the DT and thoroughly clean it with Vinegar, rinse, and repeat. I then fill the DT with the Live Rock, new Live Sand, and the water from the Live Rock container. I then move in a couple of fish, ones that have not been moved yet since being put into Hospitalization. I wait at least two weeks, then maybe add 1 more fish and repeat this process every couple of weeks until they are all back in. So we are talking about a long process. Others might have a better idea though with how to fix the mess.
The things I can say for certain are... Be PATIENT. Slow down. Research a lot. Knowledge is power. Most treatments need to be done in a Hospital Tank. New fish should go through a Quarantine Process. New Tanks shouldn't be cycled with a fish.
I hope your fish make it through! I hope I was of help. Hang in there and take no offense to anything mentioned. Just trying to get you on the right path so that your fish have a healthier, happier life.