1. How do most addons/programmers detect when your group has wiped (i.e. a specific boss encounter has reset)? I can't find any events in the API on this site...

    wowprogramming.com/docs/api/UnitAffectingCombat

    i thik you can check is boss still in fight evry raid member died.

    Could UnitAffectingCombat be used with the bossN units? I can't believe I didn't think of that:

     if UnitAffectingCombat("boss1") then
       -- Boss is in combat, therefore it has a player to be in combat with and a wipe has not occurred
     end
    

    Anything wrong with that approach?

    It looks fine. Check it in game. Should work.