This site has published an article proposing a city-state of Hebron to exist throughout the Late Bronze Age, the time of the Conquest. I will here respond to each of their points.
Blunder 1: Yes, there are numerous sites around Hebron. However, no one denies the original Hebron was at Tel Rumeida, until late Hasmonean times, only moving to the Old City on the SEern slopes after the Hasmonean takeover. The Cave of the Patriarchs was originally in a plain at Machpelah, which was near Mamre, which was near Hebron (Gen 23:19). Tel Rumeida was, in fact, a city-state during the MB IIB-C (c. 1720-1530), as attested by a fact it had a scribal class (a cuneiform tablet was discovered at the site). Jebel Nimra is just to the NE of the Cave of the Patriarchs and seems to be Persian-Roman. Archeological work has been conducted at Ramet al–Khalil and has yielded little between MB IIC and Iron IIB (1530-760 BC)-the same gap as at Rumeida. Josephus’s Mamre, a kilometer N. of Hebron, has still not been found archaeologically. Khirbet en-Nasara (31°32’56″N, 35° 5’36″E) was an Iron Age and Byzantine-Medieval settlement.
Blunders 2 and 3: As for the mentions of Hebron in Egyptian texts, these are all false. This idea was first proposed by Charles R. Krahmalkov. Contra him, it does not appear in the Amarna letters (in my copy EA 281, Moran claims the reading “Hebron” is “extremely doubtful”) Considering the fact the city-states of Jerusalem and Gath (the author of 281) were fighting over Qiltu/Keilah/al-Qilla, and Lachish and Rabud were quick to stop any Gittite southern expansion, it seems extremely unlikely Hebron was meant in that letter. As for the Ramesside inscriptions, the locales are in Lebanon, and the name is Khibur, not Hebron.
Blunders 4-6: According to Chadwick (a Garden Tomb apologist, I might add) the area N. of Hebron was a cemetery throughout the LB, and there was some sparse occupation in LB II. But sparse occupation and a necropolis a city-state ala Joshua does not make! ALL fortifications of Hebron date to either Iron IIB or the MB II. The most prominent LB site in the vicinity was Rabud (Debir?), some 8 miles to the SW. According to Chadwick, this sparse occupation at Hebron continued into Iron I and IIa. The earliest building remains at Hebron after the MB are four-room houses from the 8th century BC.