Hi finmum:
Do you know what - I think you shouldn't worry about the teacher's feelings - she clearly is deeply unconcerned about your daughter's feelings.
These are your DD's first impressions of school - and it looks like they are entirely negative. Younger children should be supported and often are allowed to bring in a comforting stuffed animal/ small blanket from home or assigned a 'helper' from one of the older Class R children - to help with shoes, buttons, etc... and to be looked after during PE. Younger children often are allowed to start more gradually - only going full-time in the 2nd or 3rd term.
Bullying (chanting I'm not your friend qualifies here) should not be allowed to carry on - and certainly should be clamped down upon in Class R.
I think you should see the Head and ask 3 questions:
Is this how you wish to welcome your newest and youngest pupils to your school?
What is the school policy on settling in children into Class R?
What mitigation can the school put in place for your DDs extremely traumatic start at the school?
My advice is set up a meeting with the Head - type out any questions (so you don't forget what you wish to say - my experience is Head's waffle to get aggrieved parent off topic (apologies to Heads but sadly true).
You need to contact the LEA about the situation - because you will have to apply for next year's school place shortly - this is especially urgent if you decide to go to another school. My advice is go to some open days and see what other schools are like in your area and talk to friends/ neighbours in your catchment. You can start fresh next year - and withdraw her from what sounds like an entirely unsuitable situation.
I am appalled by the behaviour of the children around your DD and by the fact that the teacher is so wholly disengaged with the obvious distress of your DD.
It may be better to support her learning more at home, but go to a less high achieving school (which has its own frustrations) if the environment is supportive, friendly and happy - which clearly is essential for your DD's happiness. This seems particularly cruel as in many countries children do not start until the year they are turning 6.
All my best wishes to you and your DD.