I don't know how to get the Arabs (light blue) land. I have ~1100 troops while they have ~3300. I have very good military commanders with my total skill at 30. (Ruler has 15, Marshall has 15) but I'll need more than that.
Since I have claims on the three provinces bordering Basra, I thought about doing this:
"Install Boru Yousif (me, Bey of Basra) as rightful Sheik of Kufa
Recognize x the Emir of Arabs as rightful Sheik of Kuwait
Recognize x the Sheik of Rummah as rightful Sheik of Rummah"
That way the warscore should be near or higher than my peace-value.
I can't really rely upon the Turks to help me out. They usually fight my enemies after they invaded my sole province and then quickly make peace with them.