I didn't really see anything of concern. As far as the stern voice, you kind of have to have a stern voice when you are trying to get a bunch of preschool kids to do something. She would not gain cooperation of the students if she asked in a way that the kids didn't really think she meant what she was saying.
As for the going potty, she had already told everyone to go. Having one child that didn't go then and then minutes later needed to go, was frustrating for her because now the entire class is held up waiting for this one child who should have gone when he was told to go. Can you imagine the chaos if one child every few minutes had to go potty? She was trying to keep things orderly.
As far as the Star and the kids in the circle, you can't expect preschoolers to sit and listen attentively. The exercise wasn't about that, it was about getting the students accustomed to public speaking so to speak. It didn't matter that the others weren't listening and there was a point to the exercise.
She takes your daughter from you and does not play into the tears because that would not be beneficial for your daughter. It is much better that you give a quick kiss, hug and be gone. Sitting around trying to pamper your child is not doing anyone any good and she knows that after you leave things will be fine so why prolong the tears?
Finally, the being nice part. As you said, this is something the kids say all the time. It is something neighborhood friends say to each other all the time. Answering a yes or no question with a yes or no is appropriate. Sorry if you don't like the response, but it is what it is and it's not being mean to answer a yes or no question with a yes or no. She can't tell the kids that they have to be friends with a specific child. She can tell them that they have to treat the student with respect, but she can't tell them that they have to be friends.
So, again, I see nothing to worry about. If you want a more coddling environment for your LO you should look into a home daycare.