I'm also searching for information about Rebecca McClary and Harvey Gibbons. I have that Rebecca's last name might be McClaire. Harvey's mother is evidently Rachel, b. ~1790 in OH (according to the 1850 census); his father had already died by this time it would seem. The marriage I found online lists 20 Nov 1836 in Washington, IN (LDS posting). That's all I have.
The line I'm researching goes back through Harvey Gibbons, Jr., married to Anna Baldwin. I'll gladly share what info I have should this be a line you're interested in. Do you by chance have data for these people?