The manifold is well-behaved and continuous at r=1, and mass is one of the few characteristics a black hole has other than spin and charge. Gravitons from within the event horizon won’t escape, but the event horizon itself can be thought of as the entire black hole (for everything outside of the black hole).
Thank you for that link - it was very helpful. Summarizing:
The same problem would exist for the electric field from a charged black hole. However, static fields don't need propagating photons to establish them, so you don't have to get photons from inside the black hole in order for the electric field to be established outside.
The same would be true of gravitons. But one respondent indicated that general relativity can't do a second quantization like electromagnetism, and therefore gravitons are... suspect? Impossible? Not proven? It wasn't clear to me how strongly to take that statement.
I also saw that stackx discussion when I asked the question and Google'd it. But I was surprised by the fact that while I'd seen in social media, QA, etc this question had been asked before, I was looking for something of a longer or more authoritative source that was accessible to people outside of academic study.
This discussion might help where my ability to answer your excellent question is failing: https://physics.stackexchange.com/questions/937/how-does-gra...