Because some of my kids are fostered, I have had two or more in the same grade on a few occasions. I always ask that they be placed with different teachers but other than that I haven't had any problems. As it stands now, DS6 could do a multi skip to 3rd and still be alone. None of the critical items that you listed apply, but i'm sure there are lots of little things to look at as well.

Shari
Mom to DS 10, DS 11, DS 13
Ability doesn't make us, Choices do!