Ok for plants...I had success with Rubin Sword, Anubias, Cyperus Helferi, and Wendtii (purple-ish leaves). They range from $2-$7 each. Pick ones with lots of roots at the store.
I don't like Hornwort. It takes too long to grow, and the ends go an icky brown even if it isn't dying.
I was able to keep a very mellow male betta w/ 6 leopard danios in a 16G. They never looked at each other. But I can't see keeping danios & a betta in a 10G...I mean they need to school, and
the betta will get annoyed with their hyper active movement. Plus, they prefer cooler water & a fast current, the opposite of a betta's needs.
From what I read, some corycats would be a safe bet...Don't some shrimp "boil" in water over 76 degrees?? Cory's need soft substrate or it will cut their whiskers, just an FYI. :)
ORRR....You could buy/make a divider and split the 10G...Because most of us get the "betta bug" and eventually NEED MORE!! LOL