Connie, do you have any image of these little birds with the bill showing?
In any case, the relative size compared to the skimmer, as well as the brown-tinged plumage (rather than grayer) suggest non-breeding Dunlin to me (breeding would have black bellies)...but I'd really love to see at least one with the bill showing!
I'll let the shorebird ID experts chime in as I could very well be wrong:D
I agree with the others that all the birds you're referring to in the original post are Dunlin. However, in your 2nd post there are some Sanderling as well - the paler, smaller shorebirds with the short bill, flying just above the Oystercatchers, and many of the birds on the rocks below them.