Interesting,
tovangar. While rear alleys are also a feature of some Pico-Union streets, those of the University District are considerably wider, so you are probably right about the postcard with the pillars. The second card may very well be the view from Burlington and 7th, as it is marked--I know the house at 669 S. Burlington, and it does seem a fit for the pictured row, even if it can't actually be identified on the card.