Hmm. Zebra Danios are still a bit of a risk. Even though you should go with giant danios, but no matter, they are a part of the danio family. So they should be alright with your flaming gouramis.
If your encountering problems, then you should definately take the danio out.
Your bristle nose pleco should be fine. If your tank isn't cycled then there will be a lot of ammonia inside the tank. I usually have live plants that help neutralize the ammonia, and
chlorine control in my tank, I also put in a hand full of aquarium salt, and aqua clear + cycle. I sometimes put plant grow formula just in case the iron in my tanks are very low. The more iron you have it's should be really healthy for your plants, just if you have too much iron, it will boost the plant's growth so much that the plants will be overwhelming your entire tank.
My tanks are 29, 200, and 350 gallon tank. Most of my tanks are greatly filled with a lot of live plants, I don't put plastic plants in because they look colorful, but I really don't like them. They are just a decoration.
I have a lot of varied species. I hae many different kinds of tropical fishes. About 50 different kinds in my 200 gallon tank. I usually have a few different species of angelfishes in my 29 gallon tank, and some of them are rare altum angels.
I had to wait about a few days until I can introduce my fishes into the new 29 gallon tank, I started off putting in my
betta a long time ago, and it reacted well to the water, and the plants I added in.