I was thinking of the many scenarios for Battle of the Five Armies. 

• Saeril and Kili would witness Fili's death, but accidentally split up after Kili decides that he wants vengeance. Yavanna and Tauriel try to find him, but soon finds themselves having to face against Bolg. He manages to overpower them and, right as he makes a fatal blow to Kili after he gets critically injured, Saeril flies in, and drives the Orc off the cliff, accidentally taking Yavanna with him. That is when Legolas comes to defend her by facing off against Bolg.

• After the Battle, Yavanna would find Fili, and grieve, until Tauriel and Legolas find her. There, they have a conversation with Thranduil, where Tauriel learns of her banishment, and that Legolas chooses to go north. 

• After that, Saeril and Kili find Yavanna, and join her grieving, until they all attend the funeral later on. There, they decide to stick together, and find Dis.