2) Have you looked at your research files for this unknown person recently? Why don't you scan it again just to see if there's something you have missed?
3) What online or offline resources might you search that might help identify your MRUA?
For this challenge I go to a 3-great grandfather (that is my great, great great, grandfather). This most recent MRUA would be Mary Ann (Blackwell) Ward’s father. Who was the mate of Ann Blackwell? Was she married before she married Henry Winterburn in 1838 when daughter, Mary Ann was ten years old? It is doubtful there was a prior marriage at all.