Thomas Stodhart Agar, my first ancestor to settle in Ontario, only had one son who died young, without ever marrying. The rest of the children were female. So unless T.S. Agar Sr. had brothers (and we believe he did not), our Agar name ends there.
I still haven't found any notes about John Agar and can't recall the details of our conversation, but your Agars could possibly be related to him. Holly