Hi Jasmine , my 4th go at replying to your post !! , on the late Brian Lawsons site , he groups the names Kewin with Keown, Kewne, Kewn, Keowin, Keowen and Kewen. Also Kenna can be Kennah, Kennagh, Kenagh, Keanah,Kennaugh and even Kewney !!
So based on that, possible birth for Edward , as Kewne 2/3/1815 in Malew to Thomas Kewne and Elizabeth Cowell . Edward called his first son Thomas .
Could not find any other marriage for Edward and Eleanor besides the LDS member posting , and as Sue said , they can be unreliable.
Only births I could find are Thomas (1841) and Margaret (1843).
On 1841 census (Brian Lawsons index) found E(27), E (20) and T togther , but by 1851 Eleanor and Thomas are not with Edward and Margaret .By 1861 Edward has left the IOM .
Appears Eleanor was buried 9/7/1847 , aged 26 (age right) in Braddan. Did Edward remarry ? , there is a marriage of Edward Kewin to Elizabeth Cowell 16/9/1847 in Braddan , but a little early ??.

When did Edward leave the Isle of Man ?

Cheers

David Dwyer
Sydney , Australia