Is waiver wire order determined by record first, and then by run differential (as the tiebreaker)?  I see that the draft order is determined this way, but I can't find where the waiver wire order is defined.

I've always assumed waiver order was determined by draft order.

It's not quite the same.  There are sometimes minor discrepancies from WW order at the end of the season to draft order the following season, but they're rarely by more than a spot (maybe two?), so I've never bothered to sort out the difference.  My guess is that WW is determined the same (in reverse) as tie-breakers for the playoffs, but I have nothing to support that.