each core slides into a tube with a slot on each side, this forces the air to flow over the entire surface of the core.
I have the same sentiments about the fuel, I know fuel pumps move a lot of liquid, but i'm skeptical of it's ability to effectively cool the manifold.
There was a guy running around with a AWIC setup on a WRX with a really small radiator, he needed 3+ gallons of reserve coolant to minimize soaking. Makes you wonder what would happen to the gas!
For the cryo bar, do you mean evaporating liquid nitrogen in a bar in the manifold? That would be a pretty trick setup for drag. In that category, remember that with an AWIC setup, you can fill the reservoir with ice or some other cold substance (dry ice) to get additional short term cooling.
As far as manifold heat soak goes, I'm not sure how much the AWIC performance is hampered by heat from the engine soaking to the cores. If you can keep the coolant temp down, the air would not heat up again appreciably prior to being mixed with the fuel and blown up.
thermal insulation would equal a more efficient setup, but how would you construct a composite manifold?