I wanted to respond to you because I know a little about this family, though I am not related.A few years ago a large number of letters, papers & a portrait of General John Bradstreet were located at a home not far from where I live (Albany, NY area).They were a collection from his step-granddaughter Martha Bradstreet, daughter of the Samuel you asked about.
These items were auctioned off.My mother is a friend of the owner of the auction house and she was involved in documenting the items.My mother did a lot of research on this family because she found it so interesting.
You might still be able to find references to the auction on the Net or I believe some of the items are now being offered for sale by the purchasers at the auction.In fact, my Mother told me that the portrait of the General had been restored and was recently being offered for sale.
I was just talking to my mother about your post and she gave me the following notes -- she also strongly recommended that you try to locate the book about General John Bradstreet by William G. Godfrey.I found it for sale at the ABE website.It is $100.00 -so maybe you will be able to locate it in a library, here is the link:
1) General John Bradstreet was born in Canada, his father was Edward, English Officer, born in Ireland, his mother was Agatha (French-Canadian)
2) His wife Mary Aldridge was first married to his cousin, also John Bradstreet.She had Elizabeth and Samuel with him after he died she married the General John Bradstreet and had Agatha and Martha.
3) Martha never married but Agatha married twice.With her second husband, the actor Charles John Evans, she had Frances.
4) Samuel - son of Mary Aldridge and the first John Bradstreet was an Bristish Officer who died in the West Indies in ~1784.He had two children: Samuel and Martha (the one whose papers were auctioned).After he died Samuel & Martha were raised by Elizabeth (Samuel's sister) and Peter Livius.
5) Peter Livius was in the US at one time and his first wife was from New Hampshire.Elizabeth Bradstreet was his 2nd wife and they lived in London.They almost moved to Canada when Peter Livius was appointed to an office there but were shipwrecked in Ireland on their way and never made it and never tried to go back.They died in the mid 1790s.
If at all possible could you send me a picture or transcription of the Will of Mary Aldridge Bradstreet (Bradstreet)- wife of General John?My mother would love to have it. My email is firstname.lastname@example.org.
I hope you are able to locate a copy of the book and if you have any questions about Martha Bradstreet or this family please feel free to ask and I will pass them along to my mother.Martha Bradstreet was a very interesing woman and is well know for her legal expertise in her attempts to establish her claim to the lands of General John Bradstreet in Central NY.