Question for speakers of Iranian languages (or Greek).

[Takhisis]

Ashkelon: Seems to be Ascalon, or perhaps Ashcalon (possible gen sg.: Ascalonis). Can't find anything beyond that though.

Ascalon or Ascalonia, actually. Even if it is pronounced as a ‘sh’ sound it was/is always rendered as an S in the translation (see how Chicago is called Σικάγο).

Hebron: Χεβρών (Chebrón)

I don't think so; they'd write it with an aspirated E which I am not even sure they'd be pronouncing at the time. The Arabs called it Al-Khalil (and still call it that today, btw).