You may sacrifice Sakura-Tribe Elder to search and put a basic land onto the battlefield tapped. Sacrificing Elder causes it to die, which triggers Yedora, Grave Gardener; Yedora’s triggered ability (which returns the dead creature to the battlefield face down as a Forest land) will resolve before the Elder’s activated ability that puts a basic land onto the battlefield resolves, so the creature returns to the battlefield face down as a Forest and that entering is a land entering that will trigger Zimone’s landfall. Zimone’s first landfall resolution this turn (from Yedora’s returned face-down Forest) will manifest dread; when the activated Elder ability later resolves and the searched basic land enters, Zimone’s ability will trigger again and on that second resolution you may turn a permanent you control face up (for example the face-down Forest returned by Yedora). See , , Ruling [2021-04-16], and Ruling [2024-11-08].
Step 1
Activate Sakura-Tribe Elder’s ability and sacrifice it as a cost; the creature is put into your graveyard (it "dies") and Yedora, Grave Gardener’s triggered ability is generated as a result of that death .
Step 2
The activated ability from Sakura-Tribe Elder is on the stack; Yedora’s triggered ability is also put on the stack and will resolve before the Elder’s activated ability resolves (triggered abilities go on the stack and resolve in turn) .
Step 3
Yedora’s triggered ability resolves and returns the creature card from the graveyard to the battlefield face down under its owner’s control; it enters the battlefield as a Forest land (with only the Forest land characteristics while face down) — this entering is a land entering and Ruling [2021-04-16].
Step 4
That land entering (the face-down Forest returned by Yedora) triggers Zimone’s landfall ability; when Zimone’s triggered ability resolves the first time this turn it manifests dread (look at top two cards, put one onto battlefield face down as a 2/2 and the other into the graveyard).
Step 5
After Yedora’s trigger resolved and Zimone’s first landfall resolved, the Sakura-Tribe Elder activated ability resolves and puts the searched basic land onto the battlefield tapped; that entering triggers Zimone’s landfall again.
Step 6
When Zimone’s second landfall resolves this turn (the "otherwise" case) you may turn a permanent you control face up; you may choose the face-down Forest returned by Yedora and turn it face up, revealing the original card (Sakura-Tribe Elder) and making it a creature again. Turning it face up does not retrigger landfall because it is not a land entering the battlefield (Ruling [2024-11-08]).
Resolution
Sequence and net result: 1) You activate Sakura-Tribe Elder and sacrifice it as a cost; it dies (is put into the graveyard) which causes Yedora to trigger. 2) Yedora’s triggered ability goes on the stack and resolves before the Elder’s activated ability resolves, returning that creature to the battlefield face down under its owner’s control. It enters the battlefield as a Forest land (this is a land entering). That entering triggers Zimone’s landfall. 3) Zimone’s first landfall resolution this turn (from the Yedora-returned face-down Forest entering) manifests dread. 4) The Sakura-Tribe Elder activated ability then resolves, putting the basic land onto the battlefield tapped; that entering triggers Zimone again. 5) On Zimone’s second resolution this turn you may turn a permanent you control face up; you may choose the face-down Forest returned by Yedora and turn it face up, revealing the original card (Sakura-Tribe Elder) and it becomes the creature again. Turning it face up does not retrigger landfall because landfall triggers on lands entering the battlefield, not on permanents already on the battlefield becoming lands or ceasing to be lands. See , , Ruling [2021-04-16], and Ruling [2024-11-08].
