Sorry you lost the fish.
Ammonia poisoning would be red/inflamed gills, heavy breathing, sometimes at the surface. Other times they can be lethargic/listless, not eating.
I don’t find Microbacter 7 to work well for cycling a tank and I would say ammonia is certainly possible.
Fritz turbo start or Fritz 9 is what I would recommend. The turbo works faster but has to be refrigerated so I usually just get the 9 and cycle the tank a week before a fish is added.
I would not save any water between quarantine tanks.
