Yep, a Pec - large size for a Calidris sandpiper, and yellowish legs. The other one is probably a White-rumped, note the long wing extending well beyond the tail tip (shared only by Baird's), black legs, and the grey-and-rufous mantle pattern (Baird's doesn't have the rufous), not 100% certain though (any more pics?).
Thanks for confirming the Pectoral. I knew there was something different about the other guy. My head is swimming going through all these photos. Three of us use cameras here, so I have another batch of photos to look through. I'll post if I have more pictures.