Magic Bounce will only activate once a turn. If two opposing Pokémon have
this Ability only the target's Magic Bounce will reflect the move
(i.e. the move will only be reflected once). Magic Bounce reflects the
same moves that Magic Coat does.
If you used an Entry Hazard on a Pokemon with Magic Bounce it will Reflect and land in your team, but if the Opponent used an Entry Hazard on your Magic Bounce Pokemon it will reflect and land in your opponents team. So Magic Bounce will do what it normally does.