There is no James K. mentioned in either the 1814 Peel census or in the list of peel Volunteers of around the same era - I would concur with your judgement that he + Ann Kewin of marown are the likely parents - it may be worth looking at the admin of Ann Kermode in 1833 (see Brians site).
Several of Thomas's children are buried in the small graveyard at Atholl St Methodist Chapel in Peel (see www.manxnotebook.com/methdism/chapels/peelburl.htm ) - he + elizabeth are in the 1841 census at Peel so looks as just moved there - the property they bought did not appear to have belonged to an earlier Kermode family (there were a couple in Peel) so likely they were not a long established Peel family
You have probably found the memorial notice to Thomas Cowley K. in the Manx Quarterly