Restoring coal burning fireplaces in 4 story townhouse

Neogrec, I think you could possibly remove the damper and a portion of the smoke shelf as needed working from inside the hearth, add a stainless steel liner and transition to the hearth thus eliminating the need for the smoke shelf. You could also do this by opening a hole at the mantle level, this would also allow you to infill between the existing smoke box and new flue. (Image on the right below) I would also add a rooftop draft inducer as well.

https://bloximages.chicago2.vip.townnews.com/qctimes.com/content/tncms/assets/v3/editorial/e/7b/e7b36ffc-2591-11e0-a047-001cc4c03286/4d39d9d0d980f.image.jpg

I do have a wood stove at an upstate property, it is fun to use and easy to clean, but probably not aesthetically correct for a historic Brooklyn home.