Thank you for your response. I found the children listed in the 1877 edition of Josiah's biography. His son Josiah Jr. married Mary Jane Butler, the sister to my husband's great grandfather. I have quite a bit on that line now which I put on my Facebook page- Josiah Henson Family. The link is below.
You have to request to join to view the information, but everyone is welcome. I was just hoping someone would share information with me.
I emailed the Historic Site but did not receive a reply. I also emailed Chatham-Kent Black Historical Society but with no reply. I was interested in if Rev. Josiah had performed the marriage ceremony of Josiah Jr. & Mary Jane. Also their son Francis Greenburg died as a child at Dresden but I have not found where he is buried. I'm also interested in the other son William Austin who lived in Detroit in 1930.