margaret was margt Gell m Rushen 18480325 - however there are 3 possible margt gell/gale bapt in Rushen (all in 1822) that match and are away from family in 1851 - my own money is on d/o John Gell + joney Keig (but only in that the others are eldest daughters of a farmer + a mason and would have expected to see younger sibs visiting in some census)
Edward is away from home so assuming you have linked him in 1861 we are back to henry s/o wm + jane costain with jane gawne als costean bur Arbory 18321015 age 54 but Wm not so readily identified - keep coming back to John + joney kinvig - it might well be worth looking at decree for John Gawne episcopal will 1813 as this looks the best match for John (joney's will is I think 1795)