Being familiar with LI, I'd assume the answer to my question is yes. (House has 2 chimneys now) However, even my lawyer isn't 100% sure of it. However, in my attempt to research and figure this out, I came across the following -
From the Town Of Hempstead building zone ordinance site (
http://ecode360.com/14495792#14495808)
"The following encroachments are hereby permitted:
(1) Cornices, eaves, gutters, chimneys or bay windows projecting not more than 24 inches. "
I read this to mean that a chimney would be ok. I couldn't find anything in that site talking about fireplaces.