Regarding Silla.
There’s an old map at https://upload.wikimedia.org/wikipedia/commons/e/ed/AncientEgyptJamesRennell01.jpg
on which you can find “Sile” or “Sela” at about 30.75 N, 32.25 W.
If I’m not mistaken (which is always a big if), this is Silla and the Greek name was Sile, while before they came along, it was an Egyptian fortress mentioned in the Amarna letters. Also, it was recently identified as being situated at Tel Habouah, not Tel Seif. Prior to the Amarna era it was
Tjaru, a settlement on the Way of Horus (an ancient highway to Canaan). Again I could be wrong but I have done some vigorous digging into the history of this region. :) It’s pretty obscure, so if anyone knows more/better I’d love to hear it.
In WWI there were some battles in the area, IIRC in 1916.
