Marilyn, if this message reply reaches you, first and foremost, thank you very much for sharing the "Charles Stark" information in your post referenced below; it caused a break-through in my own family research. Thank you!
With regard to making the connections between Charles Stark's second wife, Susannah Pool Roberts, and the Roberts' mentioned in your post, my family research so far has resulted in the following:
Susannah Pool(e) was first married to Joab Roberts (both of them from New York), and they had the following children:
Ezra (b. 1807 New York; married 1st wife, Clarissa Norton [2nd wife was Harriet Watson]);
Abigail (b. 1809 New York; married Abram Rynearson);
William (b. 1810 New York; unmarried);
Katherine (also, "Catharine") (b. 1812 Pennsylvania; married Richard Harding);
Sarah (b. 1816 Pennsylvania; married Edie Harding); and,
Ruel (b. 1818 Pennsylvania; married Lucinda Harris).
From these places of birth, it appears that Joab and Susannah Roberts originated from New York and, sometime between 1810 and 1812 (the births of William and Catharine/Katherine), moved to Pennsylvania.
The 1850 U.S. Census (at Leonidas, St. Joseph County, Michigan) (at Image page 12) shows that Susannah (Poole Roberts) Stark was living with her son from her 1st marriage, William Roberts and her daughter from her 2nd marriage, Susannah Stark.
["United States Census, 1850," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/MF8G-FHB
: accessed 27 Jul 2013), William Roberts, 1850.]
The 1850 U.S. Census (at Leonidas, St. Joseph County, Michigan) also shows that a lot of Susannah (Poole Roberts) Stark's children - from both marriages - were living on neighboring farms:
Abigail (Roberts) with her husband Abram Rynearson and their children (see, Image pg. 4).
Ruel Roberts with wife Lucinda (Harris) and their children, Catharine (Roberts) with her husband Richard Harding and their children (see, Image pg. 12 - on the same census page as William, mother Susannah, and half-sister Susannah).
Harriet (Stark) with her husband Leonard Schellhous and their children (see, Image pg. 14).
Ezra Roberts with his 1st wife Clarissa (Norton) and their children (see, Image pg. 19). ["United States Census, 1850," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/MF8G-2WT
: accessed 27 Jul 2013), Ezra Roberts, 1850.]
**Note: Ezra's wife Clarissa (Norton) had a sister, Phebe Norton. Phebe married Jonathan Gallaway and they, with their children, appear at the bottom of Image page 12 (below William Roberts, mother Susannah Stark, and half-sister Susannah Stark).
Thirty (30) years later, in the 1880 U.S. Census (at Leonidas, St. Joseph County, Michigan), Ezra Roberts' household included himself, his 2nd wife Harriet (Watson), and his half-sister Susannah Stark ("Susanna Starks").
The 1880 U.S. Census (at Parkville, St. Joseph County, Michigan) also shows: Leonerd SCHELLHOUS, 60; wf. Harriet (Stark), 57; son Charles, 25.
Since I am not a geneological professional, but simply a Roberts descendant trying to piece together the family jigsaw puzzle, I trust that anyone who comes across this message will confirm for him- or herself the foregoing information. Otherwise, I hope this helps to make the connections!