your getting a reasonable assesment. If you have cracks/missing mortar between the bricks that is a big red flag. If you have a chimney fire that could burn your house down. If you think you got a bad opinion call a third company in. IMO, if you determin the chimney bad i would just drop a insulated liner down there and forget the masonry repairs. There less maintenacne and last a long time, and should cost less to fix. For 6-8k you can buy two efficient wood inserts and have both installed with a liner. No way in hell would i spend 12k on fixing iniffecient open fireplaces.

"We had chimney sweeps from Top Hat and A Step In Time (Northern Virginia) check our systems. They are saying that we need to parge the smoke chamber and get some mortar work done. The bricks are not smoothe and are staggered a bit."

lol. don't deal with those idiots agian; any of them. few (less than 1%) smoke chambers are parged when initially built, and this is not a problem. often flue tiles are not mortared as well as they should be when initially contructed either, it's just the way it is. in an open fireplace, don't worry about it, you will be fine. burn seasoned wood and have the chimney cleaned once/season. it is very, very rare to ever have a chimney fire in an open fireplace due to the lack of large creosote buildup found with older airtight woodstoves, there is simply too much excess air which creates better combustion under most circumstances. don't ever talk to any of these bs artists agian, do as i suggested and you will be fine.

chimney fires are a danger in every installation, i would not burn a appliance in a chimney that has been damaged. I would get a third ON SITE opinion.