Two legs cleaned up, with the third in the foreground to see if you can tell the difference!
Test fitting the hardware:
Drilling the holes in the sockets with a hand drill wasn't easy - the drill tended to move off to the left. You can seen in the second photo how the holes aren't centered. There's still enough metal left to hold them in place, though, I think. For future reference, I'd recommend finding someone with a drill press.
Question: What should I do about the rust in the bowl at the leg sockets? I'd like to clean it up and seal it somehow, but worried that rust is all that is there!
And I will definitely be sending a photo to the donor when it's done.