The PLEP (present levels) section of the IEP is your friend. Read what they have written there and figure out if that is complete. A complete PLEP makes appropriate placement much easier. In my opinion, getting a complete PLEP should be your first battle.

The director of Special Ed should be able to meet with you over the summer, if their schedule is not full. If your child is in a summer program, the teacher there may be able to attend as one of the other team members.

Personally, I would not be too worried about having the meeting the first day of school. The first 2-4 weeks of kindergarten are all about assessing the kids and getting them into the right groups, so there will be a lot of adjustments done then (and testing the reading levels and so on.)

I do not think they can change his placement without an IEP meeting. Did you already sign the paper approving the placement in the original IEP? If not, you can check the "I do not agree" box and send it back in and go through the appeals process.