I think you are partially incorrect. I for one am quite happy that Russia is propping up Assad. He just sorta sucks, mostly by his succor of Hezbollah.
But he is orders of magnitude better than ANY of the rebel forces. So I will be cheering on Su-24s blasting jihadis.
But I think you are incorrect. Syria did not help depose Saddam. In fact Syria was a conduit for jihadis, IEDs, a hiding place for Chemical weapons, etc.
And you are 100% correct, the Gulf States created ISIS. In fact they bought weapons that we smuggled from Benghazi, to ISIS by way of Turkey. ISIS is pure Sunni.
Assad the dad was down with Bush, Sr in the first Gulf War. The Assad, Jr regime was torturing al-Qaeda for us during the second war. Yes, Sunni jihadis were pouring into Iraq from Syria but it could be the case Syria was failing as a regime then and could not stop the jihadis for whatever reason (weakness, better they die in Iraq than start wars at home, etc).