Since a philosophical zombie's behavior is, by definition, indistinguishable from that of a conscious person's, yes, such a thing would pass the mirror test. As well as any other test of consciousness based on observable behavior that we could devise. IMO that's a reductio ad absurdum of the concept of a philosophical zombie.

I agree that a lot of different concepts can get lumped under the label "consciousness", and that there is a wide spectrum of capabilities involved, not just a binary thing that's either there or not there. If the question is whether or not an animal is suffering, I'm going to go with observable behavior over theoretical concepts.