Kuhli's are great in 10 gals and up in groups of 5 or more, and pygmy cories also do well in 10 gals and up in groups of 6-8 or more.
For the pygmy cories, are you interested in hasbrosus, nanus, pygmaeus, or hastatus? It's good to know pygmaeus and hastatus are actually mid tank shoalers that do not rest on the bottom very much. Hasbrosus and nanus hang out on the bottom like most cories.
For either make sure you have a smooth substrate, especially the kuhli's as they will burrow in.
Given your current stock I think the mix that would look the best would be the cories in the 10 and the kuhlis in the 20, but either would be apropriate.