The first photo looks like one of the two different birds that I saw near the west end of the concrete bridge. Dominik Moser identified that one as a worn Glaucous-winged Gull, based on the all black bill.
Your second photo looks like the other bird I saw. Based on the descriptions in the field guide I was using, I thought it was a Glaucous Gull. However, the Taraborellis identified that bird as the hybrid. Given the silver coloring on part of that bird’s mantle, the hybrid ID seems quite plausible to me. I am hoping that whoever reviews the eBird rare bird reports will provide a definitive ID. I am certainly not an expert on immature or hybrid gulls.
TO ALL: PLEASE DO NO REPLY DIRECTLY TO MY EMAIL WITH ANY POSTS CONTAINING OR ATTACHING PHOTOS. THAT FILLS UP MY EMAIL INBOX AND CAUSES ALL SUBSEQUENT EMAILS TO BE PERMANENTLY BOUNCED (until I empty some email). INSTEAD, PLEASE JUST REPLY TO THE IO GROUP. My settings for the IO Group automatically turn large photos into links, thus keeping my inbox from filling up too fast.