Thanks for all your work on this, and for posting it here where everyone can see and comment. It’s a formalization and clarification of the way the committee and teams have already been operating, as well as some planning for the future. Both of these are really good for ClassicPress.
For the founding committee, these terms could start with the release of v1, the inception of ClassicPress (however we decide when exactly that was), or at some other point.
My vote would be to have them start at January 1, 2019, to keep terms aligned with calendar years.