This only contains data I have researched on MY side of the family. I know next to nothing about your Muir side. I can trace my French ancestors back to 1530 or so, and the Le Vayers even further; the Slaters I can trace back to about 1662.   The Ridgways ended up in Scotland, but were originally from England, mainly London, but no one seems to be able to trace them further back than about 1730 or so.  The Margots came from Switzerland and the Jansannes, whose name was often mispelt and was originally "deGensane", came from the Piedmont alps in northern Italy. 
My Orcadian ancestors stayed in virtually the same place for generations; similarly many of my French ancestors came from just a few villages close to each other in the "Berry", a part of what is now the Indre departement.  The gene pool must have been very limited, many never left their own village and married from within that village.  
Family planning was non-existent everywhere; the wives started having babies right after marriage and just kept on being pregnant every year or two.; families of 8, 9 and 10 children were common.  Infant mortality was common too, and genealogical research can be challenging  -  when a child died, they often just named the next one to come along the same name.