Regarding the Board votes, I will say from experience that unanimous decisions are a pretty high bar, at least as of the last ~10 years or so. (They were a lot easier when the Board met face to face, and it was smaller and more homogeneous.) It’s a problem of logistics more than of opinions.
(On top of that, the requirement for something to be unanimous puts extra pressure on Board members to vote affirmatively. Email votes by the Board have to be unanimous under Delaware law. It always made scheduling them extra harrowing because it makes it so much more important everyone has all the context, and all the necessary time available for the discussions and the vote. Volunteers do not always have all the time available, but the work still needs to happen.)
Requiring 2/3rds or such approval doesn’t sound unreasonable. I would probably vote in favour of such a change, either as part of this vote (although that seems logistically tricky) or a follow-up change next year. I’m still very much in favour of all three these changes.
In the mean time, I will point out that the Board votes are public record, so if any Fellows end up being evicted by the Board following the bylaw changes, it will be easy to see by which margin those votes were passed.