Yes, we also have a discounted room block at The Water's Edge, right down the street. This hotel is right on the Bay and reservations include complimentary breakfast. However, it is much more expensive than the Tiburon Lodge room block. If you opt to look for an Airbnb instead of staying in a hotel, please note, short-term rentals are highly regulated in Marin, and are illegal in some areas. Please confirm with the property owner that all necessary permissions have been granted before signing off on any rental contracts.
Northern California summers can be very unpredictable, and the Bay Area has many microclimates, so bring layers! If you plan to take the ferry from Tiburon into San Francisco, it will likely be cold and windy during the boat ride, and depending on the fog, might be quite chilly in the City. Marin is consistently warmer than San Francisco, and it will likely be in the 70s during the day, but could drop into the 50s at night. You'll want a heavy sweater, fleece, shawl, puffy jacket (really) not only for time on the water and in the woods, but also potentially for the wedding events.
Not if you are staying in downtown Tiburon. You can take an Uber from the airport to your accommodation in Tiburon when you arrive. From there, you can walk to local cafes, groceries, and pharmacies for any needs during your stay. The ferry to San Francisco, Sausalito, and Larkspur is also a short 2 block walk away. The rehearsal dinner will be down the street from the hotel, and there will be a shuttle to the wedding location leaving from and returning back to the Tiburon Lodge.