I made contact with some more informative folks today.
The Swinomish tribe planner returned my earlier call today, and he appreciated my proactive approach to involving them and keeping them informed. Since he was not familiar with the prior potential letter sent by the tribe and any specifics regarding the nearby tribal cemetery, he wanted to do some research and get back to me.
A building official from Island County also returned my earlier call. He is a non-voting member of the Ebey’s Historical Review Committee and so was able to answer general questions regarding general building objectives within the reserve.