Essentially in a 10 gallon you would be limited to only your females. If you have ten females that is fairly heavily stocked and I would not add any other fish, bettas or otherwise.
Take back your CAE. No one ever wants them in their tank as they are aggressive, territorial and grow to a decent size.
If you have not properly cycled your tank you are going to have to either stuff it with lots and lots of fast-growing, ammonia-absorbing stems, or be doing large water changes several times a week for probably the next 3-4 weeks.
If you are not familiar with the cycling process, please research it. A sorority is not the place to be fumbling your way through the ABCs of water chemistry. I just say this as a sorority is a stressful environment for bettas, and I recently had issues with my own sorority due to a sudden and unexpected ammonia spike that caused me to have to euthanise several of my females.