I am stuck with trying to trace details of a William McAllister who married an Elizabeth Clements and I think was born in Ireland around 1805 to 1012. They had a son, William, born around 1833 in Sunderland Durham. Can any one help please?

I am also stuck on Elvira Pullar who was a british subject in the West Indies and married a William Ash in Barbados in the mid 1850s before they returned to Britain where they had a daughter Harriet. William was a Soldier/Railway Labourer. Any assistance to point me in the right direction greatly appreciated.