Hello neighbors, was wondering if anyone had any recommendations for the following:

Antique doorknob / lock repair - our very old outer door has a doorknob and cassette style lock mechanism that comes loose and Ace Lock didn't seem to have the right parts / tools, but the technicians managed to secure it for a few months. It's now loose again, it seems like maybe a specialist with experience in these types of doors / locks might be needed?
Some panes in the leaded glass portion of one of our doors have cracks in them. Perhaps this can be sealed and further damage over time can be prevented?

Appreciate any and all ideas! Thank you,