Good summary. But don’t forget Qatar, which is very much in the equation. Qatar is a major player in all this.
Although there has been rivalries between Saudi and Qatari ruling classes, the two have much in common. Examples include: same Islamic ideology of Wahabism and Salafism, funding of jihadists, instigating to topple regimes in Egypt, Libya, Tunisia, and lately Syria.
It is primarily the Qatari oil and natural gas pipeline (North Field) which they want to take to Europe through Syria.
http://www.globalresearch.ca/the-secret-stupid-saudi-us-deal-on-syria/5410130
Needless to say Qatar’s Thani royal family funds Al-Jazeera network, and Qatar either outright owns commercial buildings such as Harrods in the UK, or has stakes in buildings such the Empire State. All this together with a history of close relations with the U.S. and also very much the UK makes them economically and politically very influential.
Odds believe that Qatar could be a major player in taking down Assad in Syria because they have a lot of natural gas too.
Has the Clinton Foundation gotten money from Qatar?