I cannot answer all your questions, but I have a pretty good post about it at my 'blog:

The Old Fashioned San Francisco Pacific Slope Sourdough French Bread

Real Pacific Slope Sourdough does not need refrigeration. And mostly, it would keep in the somewhat cool San Francisco climate. Now-a-days, the idiots at the "Heath" Department make bakeries keep foods refrigerated, even though that is bad for some food, notably tomatoes and onions.

The history of Sourdough bread is San Francisco is shrouded in mystery. Boudin came there from a town along the French-Swiss border in 1848 or 49. He opened a bakery in what is now the North Beach part of SF. The Boudin bakers is still using the same "mother" from 1849. My belief is that most people did not bake bread in their homes. They may not even have had ovens. What would a wood fired oven look like in a home of wood frame construction? So, I believe that everybody got their bread from bakeries. The history of the Boudin Bakery is online.