Any insight would be appreciated. I'm really upset, my child is really upset, and she's not getting the start to school that she deserves.
Honestly, I think for 4 year olds and junior kindergarten, homework is completely developmentally inappropriate. Your daughter is learning to dread school before she's really even started it. My son was in junior kindergarten and never had homework, other than the "assignment" of us reading to him every night.
I would only keep a child in junior kindergarten if they were enjoying it and learning. Otherwise, school can wait another year. That's my opinion only, of course. But full days of school at 4, with nightly homework to boot, is excessive.
I feel for your DD, she sounds so sad. I think you have done the right thing already by not making your DD do the homework and telling the teacher to stop pushing the issue. That includes insisting that your DD get her play time even if the homework isn't done. At this age, she is learning as much or more from play rather than from homework. I don't think you'll find a child development specialist that would suggest otherwise.
What kind of homework is it? Worksheets?
To prepare for your meeting, I would write out your concerns and list any points you want to make so that if the conversation wanders or you get stressed, you can bring the discussion back on topic.
I would ask, in a polite, non-challenging way, what the teacher is trying to achieve by assigning homework. S/he probably has some well-intentioned purpose in mind. If it's skills practice like counting or learning the alphabet or working on crayon/pencil skills, you can point out all the things your DD does outside of school to gain these skills aside from any assigned worksheets. I would also prepare with a little research about developmentally appropriate learning and the homework issue for very young children so you have some responses ready.
If you find that this teacher and this classroom aren't the best fit for your DD, then it's time to check out the other classes. You may find that another teacher is a much better fit. If the homework policy is a school-wide policy and reflects a general philosophy about learning and child development, then it's probably time to consider withdrawing her altogether.