Kelly and Cain are very common Manx names. If you have not already been on the IOM sites, there is a wealth of free information there as well as people who are happy to assist.
See the IOM bulletin board:http://www.isleofman.com/Community/Genealogy.aspx
IOM Family History Society:http://www.iomfhs.im/default.aspx?CategoryID=22
Also, the LDS Family Search site, which is also free:http://www.familysearch.org/eng/Search/frameset_search.asp