Akoum Firebird

• WWizards of the Coast2015-08-25
  Official Ruling
  Players can respond to the triggered ability, but once it starts resolving and you decide whether to pay , it's too late for anyone to respond.
• WWizards of the Coast2015-08-25
  Official Ruling
  The landfall ability triggers only if Akoum Firebird is in your graveyard at the moment the land enters the battlefield.
• WWizards of the Coast2015-08-25
  Official Ruling
  If, during its controller's declare attackers step, Akoum Firebird is tapped or is affected by a spell or ability that says it can't attack, then it doesn't attack. If there's a cost associated with having it attack, its controller isn't forced to pay that cost. If they don't, Akoum Firebird doesn't have to attack.
• WWizards of the Coast2024-11-08
  Official Ruling
  Whenever a land you control enters, each landfall ability of the permanents you control will trigger. You can put them   on the stack in any order. The last ability you put on the stack will be the first one to resolve (As a result, you can have those abilities resolve in the order of your choosing.).
• WWizards of the Coast2024-11-08
  Official Ruling
  A landfall ability doesn't trigger if a permanent already on the battlefield becomes a land.
• WWizards of the Coast2024-11-08
  Official Ruling
  A landfall ability triggers whenever a land you control enters for any reason. It triggers whenever you play a land, as well as whenever a spell or ability puts a land onto the battlefield under your control.

Rulings via Scryfall