Lisa, I believe Alice Cannon md John Cain(e) 1793 Onchan rather than William
Onchan Old Yard Monumental Inscription D11:
Sacred to the memory of John Cain of Douglas who departed this life 6th Dec 1821 in the 59th years of his age.
Also interred here 3 of his children: William, Unice (?)and Unice.(?)
Also to the memory of Alice Cain alias Cannan(Cannon) who was relict of the above died on the 4th of January 1825 aged 52 years.

I don't know anything about which Cain(e) line he might be from.

Donna