Tom,
To answer your initial questions...
2. Do the individual waxes themselves need vents during the investment casting process?
Are you doing the casting? Sounds like you are sending them off. The foundry will add vents it they feel a part needs it when building the tree.
4. I need to carve a new pan as the original is pretty eaten away from hard use and time. If I create a new pan in carving wax, can I just create copies with a mold then attach them to finished lock plate waxes? Yes.
Or is it better to create a new master lock plate wax (with new pan) and cast it as one assembly? No
I’m leaning towards the first option because the lock has the name “BARBAR” engraved in it and I don’t want to lose the fidelity and detail of that engraving by molding, modifying, then molding that modified wax… or am I overthinking it? Yes.
Either carve a new one or make a mold of the old one. I would make a mold with the original, after filling holes with wax,, and after injecting the mold and making a wax part, alter the wax part by filling in or building up areas. After casting you can file/clean up small areas.
5. Any best practices for plugging drilled holes in the master?
You can fill the master with wax to fill the holes..
So should I plug these holes in the master, or fill the final wax patterns with wax after making them? Either, filling the master is cleaner and faster. If the master is correct, all copies will be correct.
Hope this helps.
William