I'd prefer to try to riddle it out without resorting to cutting the bottle open. That would take all the fun out of it. If you had a reliable way to cut bottles and reassemble them with no telltale marks, then a single trick would explain all the different bottles. Much less interesting than if each bottle required a unique, clever solution.
Ignoring the wood for a moment, I'm focused on the padlock. Suppose it's not a real padlock. There are stripes on it which, to my eye, look like they might be corrugation. Perhaps it's hollow and can collapse like an accordion.
Edit: Or, per the description of the second-to-last bottle, the lock is broken down into parts and reassembled in the bottle.
Now, if you were to delaminate the lock's layers and reassemble it piece by piece inside the bottle with authentic-enough looking rivets, I can see it fitting through the neck without a problem, but I don't have an explanation for the solid piece of wood that large.
The padlock seems like the least of your worries. How the hell did the plank get in there? The only thing I can think of is the plank was split and glued back together once inside.
I think the padlock would fit if you took the shank off.
Ignoring the wood for a moment, I'm focused on the padlock. Suppose it's not a real padlock. There are stripes on it which, to my eye, look like they might be corrugation. Perhaps it's hollow and can collapse like an accordion.
Edit: Or, per the description of the second-to-last bottle, the lock is broken down into parts and reassembled in the bottle.