any steps taken after the 4 hour mark were a waste of effort and time, but no harm.
The #1 thing you could have done differently I forgot to add was reduce your lighting intensity by -40% and sustain that a week before slowling ramping up, that's a bleach control trick for all insults reef tanks may see due to errors, it may have saved the setosa's but not sure. those are pretty sensitive to insults of any type.
there is literally nothing you can do now, nor past the 4 hour mark to help the setup. prime did not help at all, but is neutral to add.
in no way does an API test have any indication of anyone's ammonia. I can produce multiple threads right now of years old reefs running 1 ppm, unfactor anything api has to say since we don't know if it's reliable at the time of render. it's not for my multiple 1 ppm thread examples.