First, welcome to the site! And wow, that is some impressive family history. Folks would be excited to have just one known family tie to the period, having a few especially with such great military and government participation is incredible. I would imagine you have spent a significant amount of time on the genealogical research side of things.
Have you gotten to visit Fort Independence (previously the Fort Adams/Castle Williams) on Castle Island? Also, do you know if any of your family members were loyalists? It would be interesting to know what paths different members of the family tree might have taken.
Fort Mifflin is close to me in Philadelphia. From my knowledge of the siege, the number of defending American forces was small and they were later mentioned by British senior military officials to have fought very bravely.
Thanks for sharing, this is so great to learn about