Will we be holding periodic elections, and if so, is this to add more moderators or reelect the existing moderators? In a broader sense, I'd be interested in hearing the level of commitment needed for this position.
If elected you moderate for as long as you want to, you won't have to stand for re-election (at least that's the way it is at the moment).
As a site grows more moderators may be added - either from the runners-up in the previous election or via a new election. Also if any moderators stand down an election may be held to find a replacement.
You're volunteering so how long you serve is up to you.
See discussion at
Yeah, It should be 'for life'.
Speaking from experience, it's not a huge commitment. This site is still fairly small and there are very few issues that come up that really require moderator attention.
With three moderators, I wouldn't expect this to take more than 5-10 minutes a day (tops) to pop in and review/resolve any outstanding issues.