It's good to be cautious but don't be too scared. The problem with a sorority is that while it may work for a long period of time things can always change. I currently have 12 females in a 46g, so far so good. In a 10g you could go with 5 girls, that's 2g per fish but I personally wouldn't go more than that. LOTS of plants, as you're doing, with a few cave structures will help tremendously. As for the two you currently have side by side right now, IME it doesn't make much of a difference. Yes removing a fish can disrupt the hierarchy & they will probably re-establish it. If you have to remove one, when you are ready to put her back, take them all out, re-arrange things in the tank & then put them all back. Good luck.