Sorry to say, but I don`t think this would work for several reasons. Hg does not facilitate the reduction by stripping the Aluminium oxide off (although it does destroy the coating in the process once it came in contact with the aluminium even at the tiniest spot). The reduction happens because Hg is more electropositive, which means that once a contact is made with the Al, Hg sucks the electrons out of the Aluminium, leading to the oxidation of Al into Al(OH)3 (the sludge you see in the reaction). It creates a bridge for electron transfer from the Aluminium to your product which is reduced (given electrons).
If there was no Hg the Aluminium would self-destroy in a very stormy way generating huge amounts of H2 in a flash. By the way this would happen any time if there was no Al2O3 protective layer as Al is very reactive and the oxide layer is the only reason Al can exist in air.
The Al powder would also have protective layer (Aluminium oxide - Al2O3) even on the tiny Al parts. The problem with powdered Al is that the reaction would happen all to quick, you would not be able to control it. Even when your foil is too thin, it becomes quite problematic if not impossible to prevent the aluminium from being consumed before your product gets reduced. Imagine this with the powdered form, it would just it itself up almost instantly.