Greetings!
In this scenario, when member 1 (Commander) goes down, member 2 (Standby) will become the new Commander. (The Standby will always assume the Commander role during a failover.)
Where priority comes into play is when multiple members (or the entire stack) are rebooted or powered up after an outage — the member with the highest priority becomes Commander, and the second highest priority becomes Standby. If there is a tie (multiple members have the same priority), rules 3 through 5 are applied as tiebreakers until there is one Commander and one Standby.
As for the Stack Revision — I believe this is referring to the version of the stacking protocol running on each switch (which is an internal value not visible in any switch 'show' command), and is associated with the version of switch software running on that switch.
If the stack is booting for the first time with stacking modules installed and cables connected, the switch with the highest stacking protocol version is chosen as the initial Commander, and all other members are automatically updated using the Commander's software image, if possible. (In some cases, if a switch is running a software version one or more major releases behind the version running on the Commander, it will not be automatically updated and will need to be updated manually before it is able to join the stack.)