Alright, after many hours of work (most of them getting my adventuring character strong enough to take on the massive mob of troglodytes and trolls in my old fortress), I have learned some important things. Maybe I'll add them to the wiki, if they're all not already there:
1. Definitely true that items in trade depots and stones, gems, and ore do not move when the fortress is shuffled.
2. Levers work as intended. I drowned my character testing this.
3. Doors that were locked when the fortress was abandoned remain so. I assume this means that levers which have been pulled remain in the same position as well.
4. The cabinets in the tomb were moved a couple of squares, but still contained all the clothing and remained in the tomb itself. The other furniture in the tomb stayed where I put it, including the artifact bed, which I built inside the tomb. I'm still not sure if all artifacts become property of the fortress when the creator dies, or if it's only furniture items. Toady?
I didn't see any of the masses of food or drink that I had left in stockpiles. I also did not see any of the skulls or leather that I had left in stockpiles. Basically, with the exception of the items in the tomb, the minerals, and the trinkets in the trade depot, I did not find any of my items. I did not explore the entire fortress yet, however, so it may be the case that they are simply hidden deeper in. This particular fortress was filled with loads of strip mines (looking for iron which I never found), so there's a lot of area to cover. If I have time I'll try to look through the whole thing.
Is there any new information here? I hope this helps someone other than me. I only wish I could get dwarves to claim items other than their clothing so that I could make treasure tombs!
I have never started the economy, as there doesn't seem to be much good that comes of it. Once you start the economy, do dwarves claim other items and keep them in their inventory? If so, does anyone know if they end up in their tombs, or if they get reclaimed by the fortress when they die?