Well, I suppose hindsight is 20/20, right? When mom would "rather not" bring the children she expects you to care for.... not good. LoL

Violence and aggression would be the major issue for me. I am glad that she's improved, but the fact that she hits someone "at least twice a day" is not acceptable. Do the other children just cower when she comes near? I wouldn't blame them!! How did mom/dad react when you started dealing with this? What was their response? Clearly, it is allowed behaviour. That would be the deal breaker for me. You are responsible for the greater good of the group here, not just these siblings.
I hope you let them stay in the pajamas until they got home. I am not going to get your kids dressed for you. We have planned PJ days all the time, and on my days off I am rarely dressed before noon if I don't have somewhere to be. But I ask that children arrive dressed and "ready for the day". If you bring them in a state of disarray, chances are they don't have their teeth brushed or their hair brushed (am I supposed to do that? and what are the other kids doing while I am helping your child get ready for the rest of our activities?), and it's not too long before parents "forget" things like sunhats or winter mittens when they are lackadaisical like this in the morning.
I am fine with people sending breakfast with their kids, as long as they are arriving before 8:30am. I don't provide it, but I will turn away "junk" food (like Cheese Puffs, lol!). The fibre bar is questionable. I would let it slide, even if it wouldn't be my choice for the first meal of the day.
I agree with Lisa. Give them a letter detailing your expectations. Put a definitive time line on it, and if there is no improvement, terminate.