Will an alloy leaching in an acid act as both anode and cathode?
You can setup a situation where one metal is acting as a cathode and the other metal acting as an anode. There will be a small potential difference due to their differences in Fermi Levels much like a thermocouple but the alloy will be at an electrochemical potential that is constant.

This is not that different than a single metal(like a piece of iron) in solution. In the corrosion reaction, the counter reaction may happen somewhere else on the iron. So the stick of iron may be the anode and the cathode at the same time.