I am a Rutherford by birth whose relatives came from Morebattle, Roxburghshire, Scotland and settled on farms in North Dumfries, South Dumfries and later Burford and Beverly.Intermingled with my family are Scotts - daughter Mary Rutherford married John Scott,also Olivers - Margaret Rutherford married Thomas Oliver, also Shellards, Bloodsworth, White, Kingsburgh, Parkhill, Miller, Hall, Reid, Beattie, Lockie and several others.Additionally, a Thomas Wallace and William Wallace are listed onthe will of my 5xgreat uncle's will.He was William Rutherford born 1807 Scotland died 1877 buried in Mount View Cemetery in Galt, Ontario.
On my 5x great grandfather's will the Sudden family is mentioned as requesting probate and I have found a Helen Rutherford married to a William Sudden - though I can't connect her with my Rutherfords at this point.
Many similar names - all in and around the same places.Have you come across any of these in your research.
In answer to your question about why they all came here - it is my understanding that often extended families travelled together and farming was about all most of them knew at the time the area was being settled.Considering the amount of open unused land it makes sense that they would start farming here as they had at home.
Good luck with your search, My best always, Dale Margery Rutherford Lupish