Which devotees' stories are promised to be told in Chapter 51, and what is the stated purpose of sharing them?

According to its introduction, Chapter 51 promises to narrate several significant stories. The primary account will be the marvelous history of how Kakasaheb first came to be established in Shirdi, exploring his deep bond from past lives (rinanubandh) and his firm relationship with Sai. While many know his stories, this chapter will reveal the lesser-known tale of his initial arrival. In addition to Kakasaheb's story, Chapter 51 states that it will describe three stories of three other devotees. The explicitly stated purpose of sharing these narratives is to soothe the hearts of the listeners and sanctify both the speaker and the audience.