Ping
I am convinced that no one group occupied the cave. At different times in history, anyone who had reason to go underground hid in those caves. David hid from Saul, the Hasmoneans hid from the Greeks, the early, pre-Pauline Christians hid there, and the Bar Kochba rebels hid there. It’s entirely likely that the Essenians also hung out there. Thus, the library accumulated there, along with some white linens, some colored wools, an armory and guard tower, the Copper Scroll, etc.