I say go ahead and have WISC done and then worry about the rest. I don't think Davidson would hold his previous IQ scores against him. He was so close and it's known that testing at 5 can cause lower score due to the ceilings. They used to admit with 148 on WPSII before so it's not like there are no such DYS kids.
I think he wasn't accepted thanks to the IQ scores and the rest of the application didn't really matter. If his AT scores are close to the cut off then you may consider portfolio, if not I wouldn't bother.
Try WISC IV and go from there.
