Never heard of anyone using the front axle on anything but a gasser. The longitudinal front springs would be a little clunky looking on a A, I would think.

Measure between the insides of the rear tires on the van, then measure the same place on the A. If they're close to the same, the diff may work ok. don't know if you are going to run fenders, but on the fenderless cars, a space of 1" to 1 1/2" between the body and the tire is about all you want in order to look right.

Slide up under the van with a socket. If you can get a socket on all the third member nuts all the way around, then it's an 8", not a 9". A 9" will require a box end wrench on a couple of the nuts. Forgot which ones.