I would say they could but they would just add one mana of your choice,,, they are mainly meant for commander decks with a legendary creature leading it...
I haven't either,,, looks pretty much the same except you have a 100 card deck with a single, legendary creature as a leader with a few different rules...
not really there is two decks for the arch enemy one the normal deck the other is the arch enemy cards which give bonuses :) not for the three other players but the arch enemy