I believe the second bird is a young subadult Lesser Black-backed Gull. My research has shown that it may be transitioning from the second summer to the third winter. Smallish,rounded head; slender straight bill; and long wings of this bird helps to separate it from similarly plumaged Great Black-backed Gulls. The white head and upper breast with moderate streaking are not uncommon in this species at this age in late summer. Birds of this age often show pink legs, but some could have yellow legs as well. I am no expert and give credit to "Gulls Simplified" by Pete Dunne and Kevin T. Karlson for my comments.