Yeast is what makes it sour, can’t have sourdough without yeast.
The sourdough has a natural yeast start (lavain) added to the dough which gives it flavor and rise. No commercial yeast.
Yes they have sourdough, along with many others. If you check their online menu it will be more detailed
They have all kinds of stuff
Yes they make sourdough but not sure if it has yeast in it
Thanks! Your answer is awaiting moderation.