I should probably look this up...
Is the LM light enough that it could be manhandled to a flat spot, if
(for example) a leg broke, it it landed intact on a large rock.


I don't think it was that light, even under lunar gravity.
Also the astronauts might not be in great shape if they did
take a hard landing...

How vertical did the ascent stage need to be?


IIRC something like 10 degrees off vertical. Which doesn't
seem like much considering that the landing field isn't a
paved airport. Must have been more than that.