I came across your post while looking for info on William O'Neal also. I am a descendant by way of his daughter Nancy. Nancy married a James O'Shaughnessy/Shaughnessy. Their daughter Catherine/Kate married Harry D. Steeves. His father was William, grandfather was Allan, great-grandfather was Matthias Steeves. Harry, Catherine and their children immigrated to Bridgeport, CT. Their daughter Margaret Mae Steeves Whaley is my grand mother. This makes William my great-great-great grandfather!!!!
When researching William in Canada you will find his last name spelled O'Neill or O'Neil
This is all I have so far. Hope it helps.