hold on a minute
are you going to fishless cycle or not? it sounds like you are, and if so, you're not quite ready yet... you won't have a totally fish-friendly enviroment until ammonia and nitrite are 0, and nitrate is under 20. it sounds like you've got a ways to go in your cycle based on the parameters you just posted, and it probably wouldn't be a good idea to buy any fish yet. also, yes, you should most definitely be worrying about ammonia. i would suggest dropping a pinch full of fishfood into the tank every night or so to increase the ammonia to help the nitrites and nitrates get on their feet. also, what test kit are you using? as for stock, it sounds like you might be going a little bit overboard on fish. this is what i would do:
5 cherry barbs
5 neon tetras
1 dwarf gourami
and the platys.
now, if you have your heart set on the cories, you could swap either the cherry barbs or the neons for a school of 5 cories.
also, the one inch per gallon rule is bogus lol, research and posting what you'd like to do here is much more reliable, and your fish will be happier in the long run. you're on the right track, but patience is a must in this hobby.