How seriously will "related" areas be considered? In ads about faculty positions, I often read phrases like "We are seeking candidates with interests in X, Y, and Z, but other related areas will also be considered"

In such cases, do candidates not specialized in X, Y or Z have a chance? Or how "exceptional" do they have to be in order to have a chance?
The answer to your (real) question is: Apply anyway. A department's hiring strategy is many times not fully expressed by an ad, never mind the fact that it's something in constant motion.