Hi Jane , Ann/Anna Kennah could not have died too young as she is on 1841 census with mother and siblings in Douglas aged 15 , her birth/christening is confusing , both are from church records , one shows christening 22/12/1825, to John Kennah and Margaret Fell (Fayle) , other shows birth 11/12/1825 and ch 30/9/1832.
Possible marriage 29/7/1845 to William Creer (as Kenah), they had son ch 3/5/1846 St Matthews Douglas , John James Creer. On 1851 census index(Lawsons Micro Site) this John James age 4 is with William Creer aged 65 !!!! and not with William or Ann. On Lawsons M S there is a burial of William Creer aged 21, Braddan 6/11/1846.
Can't find JJ Creer on IOM index for 1861/71 census. On 1881 census found a John Creer right age with son John James , although if right he would have married around 17.
Ann Kennah is difficult to find as there are too many Ann Creers , and if the William who died 1846 was her husband she may have remarried
So there amy be Creers out there who amy be rellies

Cheers
David Dwyer