Stories are part of the Spiritfarer gameplay and are one of the core elements of the game. Every passenger on Stella's ferry has a story to tell and some last wishes and unfinished tasks to do until they finally can let go from the world of the living. Stella and Daffodil are ready to help them.
Alice: In her past life, she had a husband and a daughter, Annie. They used to have a beautiful orchard. During your trip with her, Alice feels weaker and weaker, has some difficulties walking around, and she starts to suffer memory loss during which she thinks you are her daughter Annie.
Summer: In her past life, she used to be an agricultural engineer. She worked in intensive farming and became sick from the chemicals she used. She refers to her disease as a dragon. When she tried to recover, she met Rose, who seems to be Stella's aunt, and fell in love with her. She married her, and all seems to be fine for a while. But Rose also faces a disease, and ends up dying from it. Summer can't go through this and falls too. Her disease comes back and kills her. Those events may be the trigger that explain how Stella became a Spiritfarer.
Astrid: Astrid was alive during WW2, and she helped shelter jews in her home. Shortly after, she fell in love with Giovanni, because he was simple. Soon though, she found out that he was unfaithful and was cheating on her, but she still stayed with him. (plz add to this (if you know more)/correct this. this is all i know from Astrid.)
Stella's job as a nurse All the spirits that join Stella knew her in their past life. Stella was a pallative care nurse and the spirits shared their final moments under Stella's care. As you fulfil the spirits' requests, they reveal more of their life: an illness that hospitalized them, their biggest regrets, their struggle with accepting death - and, with the help of Stella, eventually come to terms with their mortality and ask to be taken to the EVERDOOR.
Individual stories of their lives which include their deaths can be found in the Lives section of their respective wiki pages.