The other William Isaac I had my eye on is William Isaac Edge who was born in Chorlton (sub-dist Hulme) in 3Q 1860.
I've just found this marriage on 30 August 1869 at St Andrew's Ancoats which adds a bit more interest to that one:
Benjamin Locker,21, bachelor, striker, 41 Buxton Street, father William Locker, wireweaver;
Eliza Dorothy Edge, 23 , widow, 1 Baker Ct, father Enoch Barlow, fustian cutter