Which devotees' stories are announced in Chapter 51, and what context is given for their inclusion?

In Chapter 51, the author sets the stage for several narratives that will be detailed later. The most prominent story introduced is the 'marvelous account of how Kakasaheb was established in Shirdi.' The text notes that while many of Kakasaheb's stories are known, the specific history of his initial arrival is not. This journey is attributed to his 'bond of past lives (rinanubandh)' with Shirdi. In addition to Kakasaheb's origin story, Chapter 51 mentions that it will also describe 'three stories of three devotees.' The context provided is that meeting a Sadguru is a result of the grace of the Supreme Lord and the merits accrued from past lives.