The man in black fled across the desert, and the gunslinger followed
1. When it says break all other champions... it means ALL of them... even yours?
Example being Angel of Death, and plague.
Yes, all Champions expect any specifically excluded would be broken.
2. The non-turn person can still play events at the end turn phase. And then each get a coin back for his turn?
Yes, the end of turn allows the other player to play cards (events or Ambush Champions). When a player turn starts, both players loose any unspent gold, then gain 1 gold, so you can spend the gold at the end of the opponents turn, then get 1 gold for your own turn as well.
(Practically... In battle the defender should always have a coin to defend?)
The defender will always have 1 gold available when the first attack is declared.