Drone 3 as follows...I still haven't found these guys on the ship, but it's big and they aren't!
If it's my DLL then one is walking along the top girder that runs from the living/cargo area to the front of the ship. One is walking along the top right side of the living/cargo area front to back and one across the front of the living/cargo area left to right. The problem is that they are part of the model and it's really hard to see them because of visual clipping.
If I were to do it again I would make them ships and then attach them to moving attachpoints. That way you could focus on them to watch them.