Let me preface this by saying I'm a newbie and seem to be falling into
every newbie trap there is.

I fishlessly cycled my tank over a week ago...it took a week for
anything to happen, but over 5ppm ammonia (bottled ammonia) eventually
turned into about 40ppm nitrate...the nitrite level never reached more
than 0.50ppm during the entire cycling process. It's as if as soon as
the ammonia-eating bacteria turned the ammonia into nitrite, the
nitrite-eating bacteria turned it into nitrate.

Then I added 5 small (young?) golden barbs, 3 small ottos...and too
much food (I got regular Spectrum--I'm realizing now it might be too
big for them, and they're still skittish and hiding under the plants).

My tank stinks, but my Ammonia Alert never showed any ammonia. I could
see the Spectrum pellets disintegrating, but no ammonia activity.

Tonight I checked all my levels:
pH 7.2
ammonia virtually 0
nitrate 20 ppm
nitrite ~2ppm!!!!!!!!!

I almost had a heart attack.

I quickly did a very quick 2/3 water change (yes, too much but I
panicked), using AquaPlus to eliminate chloramine, and now my levels
a

pH 7.4
ammonia 0.5ppm (because of chloramine--my tap water is around 1-2ppm)
nitrite now 0.5ppm
(didn't check nitrate again, but it's probably dropped to less than
10ppm)

I can't add salt to help them deal with the nitrites, because I have
ottos and apparently they (being scaleless fish) can't tolerate salt
at all.

I have three questions, and I implore you for sage advice:

1) I've read that nitrite-eating bacteria establish themselves more
slowly...but weren't they still there from the fishless cycle? Why
aren't they keeping up with the ammonia-eating bacteria?

2) Why do my golden barbs ignore the food? They seem to eat it
aggressively for about 5 seconds, and then run back under the plants
while the pellets rain around them. Then they ignore the pellets for
the rest of the day. Is it too big? Are they too dumb to see the food
in my (similarly colored) reddish-brown gravel?

3) Why are the barbs almost always hiding under the plants? They come
out and "play" every once in a while, especially when I turn off the
lights, but generally just bunch up in a tight group under the plant
fronds.

Thank you in advance.
Jason