I would agree with #1 completely - when DD started school she started in kinder and went to gr 1 for reading, then she went up for math as well, then mid year she moved up completely. But, because they were so used to seeing her in class, they forgot to let her in on those routines, which weren't routine to her and she ended up in a puddle by the end of her first day in gr 1.
I would also add to talk to the teacher whose class your child is skipping into. While the school may be willing to try this out, the teacher may not be on board with the whole thing. This could ruin the whole thing.
