Maybe I misunderstand your second theory, but it sounds to me as if that requires some sort of strategic reasoning, which I presume to be absent
Having a feeling of recognition in the face of something one has been previously exposed to requires and involves memory, but that is not the same thing as fully recalling what it is. That's why I didn't go so far as to say that the zombies were remembering anything. I don't think the memories are clear at all, but they are vague and at best dreamlike.
However, as far as I know, people don't instinctively want to sit in church; they are indoctrinated to do so. I thought the zombies were congregation in church and around FEMA, because they vaguely recognized those places as being important. I don't think that's the same thing as saying that they have any memories of those places, even if they were actually in those very places before, but I find it similar to the idea that they do, since it depends upon the zombies retaining some of their social conditioning.