Hey, I'm not sure if this would be the best matchup. Keyhole cichlids typically need to live in groups, the stress of this might cause your keyhole cichlid to start bullying the betta. Here's a good article on some great tank mates for your betta though.
It really does depend on the temperament of your betta, especially with the chili rasboras being quite small. You should also make sure that you're not overstocking the tank as well. What size is it? If you're not sure about the temperament of your betta I definitely wouldn't do it in a tank...
My betta used to do exactly the same thing. I was making sure to feed him enough and he still tried to get the algae tablet I'd feed my shrimp. It never did him any harm though, and he lived to 4 years old so I wouldn't worry about it that much!
It always depends on the temperament of your female, and while females generally aren't as aggressive as males they are still known to be aggressive. Some ways you can help reduce the chances of your female betta being aggressive are to ensure you're keeping them in a large tank, providing...