A local percussion store described these lugs as "Slingerland knock-offs, and the t handles and claws Ludwig knock-offs".

I wonder what would make a lug Slingerland vs. 'Sling. knock-off'?

If I were to add the rest of the bass drum claws, what should I search for?

Thanks again

Parts are not that terribly expensive. I would stick w/ Slingerland, & seek out the best parts deals I could find. Looks like your main battle is the effort & labor to clean up those shells. (some of those holes look really mangled).

Yeah, all over the map there, with all the different hardware.

Looks like 3-ply shells, but which brand?

That's a wide open canvas there, you could put any wrap you want on them, do some staining or have a natural finish. Looks like they've been through enough!

Throw on some matching lugs that fit the holes, and you're in business.