I have some reference material on Stewards.In "Skowhegan on the Kennebec" it states that Dr. William Steward was married to Sally Hood.I have seen Sally used as a nickname for Sarah before.There is no listing of any children to this marriage in the book.
I also have copies of portions of the information of Sprague's Journal of Maine History, Ancestry of the Stewards.This one does not follow the line of William and Sally (Hood) Steward either.In the descendants of Deacon Thomas Steward it states that John Steward married Mercy C. Steward on Sept 3, 1818.Mercy C (Steward) Steward was born in Canaan, May 5, 1795 and died in Monson July 30, 1866.She was the daughter of Dr William and Sally (Hood) Steward of Canaan and Bloomfield.Dr. William Steward was usually called "Dr Bill"
It could be that Roxanna is a younger sister of Mercy Steward but I don't find any mention of her.I may have something in other material I have when I get a chance to check it.
In "Skowhegan on the Kennebec" it states that the town of Bloomfield was set off from Canaan on February 6, 1814.It seems when we were there and researching the town names were used interchangeably.