Charlotte judging from age in 1851c (they are both still at Ballahick (strictly a house on castletown road) he is a cartwright age 74 - she 69 born braddan which fits well with d/o John Shimmin + rebecca creer (rebecah is I think d/o John Creer + Jane taggart (bapt Braddan 17561015 - however the Creer name has been well researched and you should find most wills transcribed (see www.iomfhs.im/lawsons/wills/_will_index.html)

John born malew might well be s/o Wm Kneal + elinor Quine bapt Malew 17770112 - the quine line has also been well resaerched so I suspect that this will be easy to trace if confirmed