I think Bailey and Buffy were separated at birth. They're the same age, and they have had pretty much all of the same developmental issues!
Right now, Buffy's having the same issue with "come" that you describe with Bailey and agility. She knows the meaning of the word "come," but she just chooses to disobey. (I posted about this in another thread.)
I do think some of this is having a drive-y young dog in the midst of the "terrible twos," but that's not all of it. Some of it is just their personalities and them being little princesses that know they are cute and beautiful.
I tried agility with Buffy at 8 months and she honestly couldn't handle it. She was doing some of the same things you describe with Bailey. Also, I happened to end up with a bad agility club for me and I didn't find it enjoyable.
I was "too green" a handler for Buffy, and I did not appreciate the agility people giving me tips. One of the things I have noticed about many agility classes is that they train the dog when they really need to train the handler.
Our puppy class trainer was ridiculously wonderful, and as a result, I am now spoiled for any other class, including agility and dog therapy.

Luckily, I'm taking another class from that trainer soon... "Outward Hound." And I'm going to try and get Buffy certified with Delta, but we're not there yet.
The other thing that helped me was hanging out with Markley, our neighbor dog. He's a cockapoo, a little younger than Buffy, and he is such a boy.... really eager to please, none of the Sheltie reserve, and he and Buffy play adorably together.
It was so hard for me to find a good playmate for Buffy. She's picky, and I guess I am too. (I heart Markley's owners, who live in our building.) So whenever I am getting irritated with Buffy, I just go play with Markley and it's awesome.
The other thing that I have been doing is NILIF. I'm sure you're already doing this, but it's worth a refresher when the dogs are this age.