How should shelf angles be detailed at outside corners? Can the shelf angle stop at either side of the corner, or should the shelf angle be mitered or notched in order to fill the corner?

I generally recommend mitering shelf angles at corners. Another approach is to extend across the corner the horizontal leg of the shelf angle that will support the brick that crosses the corner at that level. Although masonry constructed in running bond does not need to be supported at the corner, mitering or coping the angle is necessary to support the flashing and to create an open expansion joint beneath the angle.