I see a very bad and blurry picture If you don't see a Mint Mark then it is not from Denver or San Francisco
No, but I wouldn't risk money betting on (say) a 1928 instead of a 1928-S based on a photo this poor.
I don't see one, a better quality picture zoomed in on the area in which a MM would be could help us give you a more definitive answer though
How in the world can you tell? All I see is a stain obscuring the E, and a ton of JPEG (image compression) artifacts.