Are there other works besides the Shri Sai Satcharita that could be used for a detailed group study of Sai Baba's life?

Based on the information in Chapter 0, it seems unlikely. The text mentions works by the poet Shri Dasganu Maharaj, but clarifies that while one can perform a Parayan of his works, they are not suitable for a detailed study of a single saint's biography as they are not comprehensive. The preface explicitly states that in Maharashtra, apart from the Shri Guru Charitra (about a different saint) and the Shri Sai Satcharita, 'no third work written in such detail is found.' This suggests the Shri Sai Satcharita is the preeminent and most appropriate text for this purpose.