Hi there! My main advice would be to just choose one method that makes the most sense to you and stick with it. Probably what's worse is to keep on shifting between different methods, which is a recipe for disaster.
At the end of the day, everyone in the hobby does things differently and still end up in the same place, so it is not like certain methods are absolutely right or wrong or anything.
Of course, there are certain things that are facts that cannot be debated, so I'll share them with you first.
1. Presuming you are using the API nitrate test kit or similar, the presence of nitrite will cause it to falsely read higher. The reason is because the test kit actually converts a portion of nitrate to nitrite then measure that instead of directly measuring nitrate. So if there is nitrite present, the nitrate test kit will falsely output a higher nitrate reading. When I first heard of this it kinda blew my mind, but after googling, turns out yeah it is true.
2. Nitrite is not toxic to marine fish, at least until it reaches very high levels. When I first learnt of this, it blew my mind too because for freshwater fish, this is absolutely not true. But yes, because of saltwater, things are very different. Here, check this out:
http://reefkeeping.com/issues/2005-06/rhf/index.php. That article is by Randy Holmes-Farley, the guy our chemistry sub-forum is named after so he's legit.
3. Ammonia is definitely toxic to all fish, marine or freshwater. But there is a limit as to how much causes toxicity, and of course there are products like Prime that can temporarily detoxify ammonia.
So moving on to my personal opinions/methodologies that may differ from others.
The suggestion to add fish to produce ammonia to keep the cycle going is a very old method, basically a fish-in method that in my opinion is unnecessary, especially given your circumstances. After all, you are already using Microbacter QuikCycl, which is just dosing ammonia.
There is no difference between ammonia you dose that way and ammonia produced by fish.
I would not recommend adding any fish until your aquarium can handle ammonia well enough. I have a handy guide that you can follow, including reasonings for why:
The main caveat is that you can add fish even if nitrite-oxidizing capacity is 'not quite there yet', given the above explanation that nitrite is non-toxic to marine fish until it reaches high concentrations. High concentrations as in probably over 100ppm for death, but potentially 25ppm is enough for disease. I doubt you'd ever reach 25ppm nitrite unless something goes wrong, so that's why it is probably not too much of a worry. But it is possible, so I am just giving out a warning now.
Personally, I like to ensure that both ammonia and nitrite reads 0 (or close enough) after dosing 2ppm ammonia, but that's a personal preference. Just to be sure, essentially.
