Oh don't worry, three days is nothing....as mentioned previously, they can go weeks without eating. If she appears fairly active with good colors and no other signs of illness, theres not much need to worry.....shes just adjusting. Keep offering her food and removing what she doesn't eat.
You can head out and pick up a couple of different pellet brands or some flakes and try those if you like as well, or you could soak a couple of pellets in garlic juice to get her attention a little bit if you like.
And about your question about keeping multiple females....
If you're considering keeping females together, you are considering whats called a Betta Sorority. While this is possible in a 10 gallon, you not just looking at tossing in a couple more females and that being that; you'll want a group of at least five females(which is about the max for a 10...along with the frogs it may be pushing it stock-wise though)in a heavily-planted and well planned out tank. Generally Sororities aren't recommended for beginners because they require a slightly more experienced eye(it can be hard for a beginner to tell when the inevitable bickering and nipping goes too far), and even in the most perfect considers with the most experienced keeper things can take a turn for the worst in the blink of an eye. Females can be JUST as aggressive as males, so theres quite a bit of risk involved keeping them together. Because of that, you'll also need a backup plan....separate tanks for each fish, and the time/money to care of them individually if things don't work out unless you can find a way to re-home them.
Take a look at this thread: http://www.bettafish.com/showthread.php?t=29402
and if you're still interested, I suggest scowering the internet for more information; you'll want to do all the research and prep you can if you really would like to keep multiple females together.
I'm afraid there aren't too many other options for your tank.....the ADFs kind of limit your stocking options now. Even if you start a sorority, you may have to get the ADFs their own tank or re-home them. You MIGHT be able to divide your tank in half, keep the ADFs and one female on one side and add another female on the other side...but I'm not sure how well that would work out.