You bring up some valid points, and I will keep them in mind, especially about Eliza. However, in regard to the naming pattern, there are a few things I'd like to leave on this list, just for the sake of the archive, if nothing else. As for the women, your pattern seems to hold, as the first daughter of record, Sarah, may also be the name of Eliza's mother, as you mentioned Sally is dim. of Sarah. The second daughter, Mary, would then indicate the name of John's mother, if this pattern holds for the Irish as well as the Scots (Eliza was b Ireland, as was John). And the third daughter, Elizabeth, would be a form of Eliza, and indeed, her cemetery records (though nowhere else) list mother Eliza as Elizabeth.
However, the naming pattern cannot be applied to the sons to determine the name of Eliza's father, as they were not her children. James, John and William were sons of John Stevens' first wife, Catherine Kelly, who died abt 1858. I do have cemetery records indicating that Eliza and John possibly had a son (the child's parents are not identified in the cemetery records) named Samuel. However, I've not run into any indication that John's father might be named Samuel. I had taken that to possibly be a namesake from the Murdock side, as Eliza had a brother by that name, and it led me to wonder if her father's name might be the same.
At any rate, wanted to document the parentage of the sons, lest anyone in the future wander through the archives and assume I was indicating that they were children of Eliza Murdock.