Wow, wow, wow! I am so incredibly impressed with this dog!
So on Sunday I took Bella to agility again, kept her in her crate, and I varied my rewards more. [She's getting sassy -- if I'm not treating her and she's behaving she will stomp at me and sometimes bark in my direction!] She stayed in her crate most of the day until I took her out while Mom worked her dog Tinky. She was great with Tinky, and usually she has a hard time controlling herself, even if Tinky's just playing, she always wants to chase and tackle her (not in an aggressive manner, but in a rough play way). She behaved great - really focusing on me, and behaving, so other then just clicking and treating her as a reward, after Mom put Tinky away, I let her do a jump or two and the tunnel a few times (she loves tunnels!).
I worked her some with all the other dogs away, and then said "okay, will you bring your dog out?" to the lady training with us. She just walked him around her -- on leash -- for a bit, then I had her jog past, then when I was really comfortable with how she was behaving, I said you do the tunnel on the other side of the barn. Bella loves tunnels, and hates when other dogs do them, so this was a "tougher" thing to ask. I asked Bella for nose touches, spins, downs, 'dead's, sits, etc., while the woman was doing it, and Bella literally didn't flick an ear.
After that I had her jog around some more, and Bella was REALLY focusing on me. She'd look at the other dog every once in a while, but if I said "Leave it." she was very quick to respond to that command.
I am so pleased with her -- Good Dog, Bella!