I believe the group of devotees from Madras mentioned in Chapter 29 were followers of Gajanan Maharaj. Can you confirm this?

The information you have seems to be incorrect. The text from Chapter 29 of the Shri Sai Satcharita explicitly states that the group of devotees from the Madras region belonged to the Ramdasi sect, not that they were followers of Gajanan Maharaj. In fact, there is no mention of Gajanan Maharaj in these verses at all. The chapter narrates that this group of four travelers, who were on a pilgrimage to Kashi, stopped at Shirdi for Sai Baba's darshan. It is mentioned that they performed devotional singing with great enthusiasm in their Ramdasi tradition and that Baba, pleased with them, gave them eight rupees and eight annas.