That would overstock your tank. You are still very limited in a 10 gallon. A 10 gallon can really only fit a betta and another school. If you get fish like neons, you want them to be in the biggest group you can as if they are kept at their minimum, or the minimum people say on here, they will most likely nip.
You could house neons, about 7 no other fish besides your betta, provided your tank is fully cycled, you understand their needs, and keep up with water changes. One thing to understand, from being bred so much, neons have terrible immune systems and will usually die within a year via crappy genetics.
Don't get all males, they will fight. Female plagues would work better. Usually when they give birth, they have babies not eggs, usually the other fish and the mother will eat the babies. Just have a petstore take them or cull them.
Forgot to mention, cories, like most bottom feeders, need a sand substrate. If you have gravel and aren't willing to trade it for sand don't get cories.