I believe you are correct. Nothing that I see says that the Bobo's have any idea what happened. I don't believe they are the kind of people who would allow searchers to come in and waste valuable resources and time to search if they knew where Holly was. Now, on the other hand, LE is not audibly calling for public searches. We have no idea if what they are doing is related to the Bobo case or not when we see any movement at all or hear rumors.I dont think the Bobos know who took Holly. LE may have a prime suspect but they havent told anyone. I also think the family had some early ideas that may have changed as time goes on. I know 1 rso is still on a possible short list. He still has an unnamed associate.
I believe you could be correct, too, that their theory changed after the first days. Look at how many "viable" suspects these forums have discussed by name, not to mention the unnamed ones. However, I would expect that they've been personally able to rule out some folks but not others. It must be terrible living among folks and not being able to trust them all.