-I used Ettifaq FC from Saudi Arabia League, not CD Palestino. Ettifaq FC isn't an option to choose for some reason.
-Most of these players have Palestine descent, making them eligble for National Team.
-http://www.transfermarkt.com/detailsuche/spielerdetail/suche/5226568
The website above, which is quite useful and reliable shows that 
-Anibal Capela
-Mauricio Ramos
-Moustafa Zeidan
-Gabriel Somi
All these 4 are descendants according to that site, which is a reliable site once again.
Digging more research I found that Dani Schahin and Joel Abu Hanna have Palestine heritage from this site.
http://footballpalestine.blogspot.com/p/players-of-palestinian-origin.html

Now onto subs and a goalkeeper, which you'll have to create these 4 players. The links next show players who have been previously on FIFA but were removed. Three position players are from FIFA 16 and Goalkeeper is from FIFA World Cup Video Game in 2014.
Ashraf Al-Fawaghra http://sofifa.com/player/215676
Pablo Tamburrini http://sofifa.com/player/214428?v=16&e=158227
Jonathan Cantillana http://sofifa.com/player/226943?v=16&e=158242
Mohammed Shbair http://sofifa.com/player/194347