1)
What does the Pasuk mean when it says "that the Pelishtim emerged from there"?
1.
Rashi: From both Pasrusim and Kasluchim, who tended to swap wives, and it is from between the two of them that the Pelishtim emerged.
2.
Ramban: Kasluchim lived in a city of the same name, which was in fact, part of the land of Kaftor, his brother. It was some of the Kaftorim (descendents of Kasluchim) who left Kaftor to go and seek a better area to live, and who captured the land of Pelashes (leaving their original land to their brother Kasluchim), which became known as Pelishtim. 1
1
See Devarim 2:22.
