Help with logistics for 15-person bike tour

Hey there San Juander'ers!

I'm planning a large 15-person bike tour with family and friends in late August/early September and wanted to reach out to this community to get general feedback on logistics, route planning, must-do/must-see activities and places, and any tips on great places to stay for large groups.

Logistics

We're working on booking ferry reservations for the one vehicle that will be supporting our ride because we've heard that those can sell out and that seems like a crucial component. Is it correct that we only need a reservation for the Anacortes > Islands leg of the ferry, and that the inter-island ferries are all first-come, first-serve for vehicles?

Are foot passengers with bikes free on the inter-island ferries?

Route Planning

We were originally thinking of doing a clockwise 1. Lopez; 2. San Juan; 3. Orcas; 4. Back to Anacortes order of island hopping.

Any thoughts or considerations for alternative routes we should keep in mind?

Must-do/Must-see

The things on our short list are kayaking in Roche Harbor, biking Mt Constitution on Orcas, Deception Pass back on mainland. Anything else you would recommend for a bunch of first-time island visitors?

Large group lodging

Looking for any recommendations that anyone has for lodging options for a big group. We're flexible on a combo of hotel, motel, hipcamp, campground, airbnb, really anything. We'll have a few older couples who will want bedrooms, but we also have 10+ people who will be bringing tents and willing to camp wherever is available.

Those were the only question areas that we came up with at first blush, but would really appreciate hearing any other ideas or recommendations that we should be considering.

Thanks in advance for helping out a big group have a great time in a beautiful place!