You can use the alh pistons but there is one issue. Since the top ring groove on the alh piston is higher than the aaz piston, the ring can catch the ring groove in the cylinder wall. Even the ahu or 1Z pistons have a higher top ring groove than the aaz but not quite as high as the alh pistons. If there is no ring groove in the cylinder wall or you've bored to the next size then your fine. I'm sure you know this but you also need tdi delivery valves, injector lines and valve cover to make it all work.
And if you don't use TDI delivery valves???