It depends on the filtration, aeration, plants, and the number of water changes/how much you do. Though, cories are schooling fish, as well as the danios. So, instead of the cories, I would do 2 more zebras and 4 more pearls. This way, you'll see them hiding less and they'll be less stressed. You could drop the tetras and just get 1 honey gourami. If your filters can handle it, you keep up on your water changes, and you test your parameters and make sure they're still okay, it's totally fine. "Overstocking" your tank doesn't matter as much as long as your fish are happy and have enough space and your parameters are good!