A big hitch in our testing is that it is not a very good test kit. When you are sure you don't have nitrite, it may simply be that your eyes do not read the test colors or the colors are not totally correct. Hobby level kits are more an "indication" rather than a true reading. Take the test to a different light and you may see a different reading. But the main point is that you do not have a significant nitrite level to worry about.
The difference in first cycle results and results when using old media are quite different. We often find the first time, it seems to take forever but the next it bounces right up.
And then I would certainly not worry about the amount of fish load you will be adding as the fishless cycle is designed to cover just that point so that the fish are not facing ammonia. Assuming you are adding the correct recommended level of ammonia, that ammonia should cover even a massive addition of fish. That is what it is designed and expected to do. While your case seems dangerous, compare it to somebody starting a large African cichlid tank. It is often necessary to ship the fish, add them all at one time to help control territories and the fish can be very expensive. I have some fish which sell for $45 each with local pickup.
So the fishless cycle is the only way to go for those folks and it does the job very well.
One point that may be missed is that it vital to continue to feed the correct amount of ammonia to maintain the high level of bacteria until near the day the fish are added. Just because the bacteria grow quickly doesn't mean we should lack off and let them die while waiting around for fish.
Your tank has arrived, now maintain that high level, either with ammonia or fish waste?