On the topic of dust control it helps to block the chimney during the
dismantel process. Depending upon the size of the chimney you can use a
bed pillow or ol couch pillow to plug the damper. Or if you are looking
for a real tight seal you can use a chimney balloon like the ones on
this website www.chimneyballoon.us
I know they are listed as insulation devices but they help when
demolishing a chimney too. Dust downdrafts so easily into the living
area when working on the chimney. You want as tight of a seal as you
can get.
I think you are getting a great deal at $3K. If the mortar is still
mostly good on the chimney that dismantle can take days to do.