Yes, you are right, Eric. That Lezayre bapt 08 MAR 1806 Lezayre (s/o William Corkill and Isabella Kerney) certainly fits the best of the ones we have looked at so-far. Also William had a daughter Isabella.
And the other two Lezayre bapts for William Corkills on 15 SEP 1805 Lezayre (Father: ROBT CORKILL, Mother: JANE LORD) and 06 NOV 1807 Lezayre (Father: JOHN CORKILL, Mother: JANE KINREAD) would be more likely to be the parents of the William Corkill Rob is looking for than Edward Corkill of Maughold.

I'd still be interested to know what happened to Edward, and think one of the 1820 wills could be his.

Sue