Not sure (and maybe someone that knows a bit more about it (but not skroesec ) can tell me) you can fight actual wars by droning.
The FSA by itself is unable to defend its territory, nevermind an FSA that is divided in two fronts (assad west, estremists east). You'll need way more than droning to achieve a stable FSA governing Syria.
Anything less than full invasion and front lines fighting will get Syria stuck in a 50 years civil war in my opinion.