Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.
Haven't checked any keys to verify, but most of the little late-season Cahill-looking duns are Leucrocuta. If I had to guess at the species, I'd say hebe (Little Yellow Quill). It is probably the most common L. spp. in the East and has a long hatching period that extends well into the fall.
I would also agree that the spinner you photographed is the same species.