Was Shirdi empty before Baba settled there? Were there any other holy figures around at that time?

No, Shirdi was not devoid of holy figures before Sai Baba's return with the wedding party. Chapter 5 of the Shri Sai Satcharitra explicitly clarifies this. The text mentions that before Baba's arrival in this manner, a saint named Devidas had already made Shirdi his home. Furthermore, another holy person, Janakidas Gosavi, also came to live in Shirdi around that time. This indicates that the village already had a spiritual atmosphere and was home to other saints before Baba's presence became widely known.