Where to find the Fang Yao and Complete Her Quest

First Meeting - Cloudspire City: After defeating an enemy upon entering the city, interact with the NPC to meet Fang Yao. She'll ask about her father. Return to Hillswatch, find his burial site behind a house (take the left path at the intersection, then behind the house), use the Examine Pose to get the Shu Silk Scarf.

Second Meeting - Cloudspire City: Return to Fang Yao's house with the Shu Silk Scarf. She will give you three Sapphire Lotus Seeds.

Third Meeting - Shaft Entrance: After defeating the boss at Treasure Trove, find the Bloodied Paper behind the area. Take the lift down and meet Fang Yao. Agree to help her find her sister, Ling, and she will give you a Medicinal Powder and teach you a song.

Fourth Meeting - Wedding Hall: After defeating the boss at the bottom of the Shaft, refresh the Shrine at the Wedding Hall. Fang Yao will give you Fang Yao’s Hairband and Fang Yao’s Light Gown.

Fifth Meeting - Refugee Camp: In Chapter 3, after leaving Battlefield Site and heading to Refugee Camp, you'll find Fang Yao and He Youzai near a campfire. Speak with her.

Sixth Meeting - Annalum: In Chapter 4, enter Annalum and speak with Fang Yao and He Youzai. She will give you a Soulgrass.

Seventh Meeting - Reverent Temple: In Chapter 4, find Fang Yao to the left of the Shrine. Speak with her twice to receive the Research Journal - Scrap 3 and Ring of Samsara - Cause. These are vital for two endings. (Note: Giving the scrap to He Youzai in Reverent Temple yields Ring of Samsara - Effect, which combines with the other item in Chapter 5 for specific endings).

Eighth Meeting - Annalum: Fang Yao returns to Annalum. You can only interact with her if you are with He Youzai.