Lion's share of foreign fighters in Syria are affiliated with an al Qaeda franchise

Adding to this the domestic Jabhat al Nusra fighters ... (and the numbers below are those of the DEAD, tallied by an Israeli 'consulting firm'.

'Muhammad Yassin Jarrad, who was killed on Jan. 16 near Al-Suwayda, Syria, 

was the brother-in-law of Abu Musab al-Zarqawi'

"... Given the recency of its occurrence and relative geographic proximity, it is
appropriate to compare our results to those of prior studies of foreign fighters who joined  the jihad in neighboring Iraq. In October 2005, one of the authors of the present report  used an analogous methodology to conduct a study of 326 foreign fighters reported killed  in Iraq over a 28 month period.1
 Aside from Syrians, the most prominent nationalities of  the fighters were Saudi Arabia (52%), Libya, (5%), Kuwait (5%), Jordan (5%), and  Lebanon (4%). Only five Tunisian fighters were recorded during the entire study,  comprising little more than 1% of the total polling group. The U.S. military drew similar  conclusions from the so-called “Sinjar Records”, a cache of highly detailed and revealing  personnel files on 595 Al-Qaida foreign fighters in Iraq from 2006-2007.2
 According to  researchers at West Point who gained early access to the Sinjar Records, “Saudi Arabia  was by far the most common nationality of the fighters’ in this sample; 41% (244) of the  595 records that included the fighter’s nationality indicated they were of Saudi Arabian  origin. Libya was the next most common country of origin with 18.8% (112).”3
 Fast forward to the conflict in Syria and the present study and we find that some  trends have stayed constant, while others appear to reflect the changing politics of the  post-Arab Spring Middle East. Once again, Saudi Arabia and Libya figure among the  most prominent two nationalities of foreign fighters in our data sample—however, this  time it is Libya that is the undisputed leader at 21% (59) versus Saudi clocking in at 16%  (44). It is hard to dispute the outsized role that Libyan fighters have played in the Syrian  uprising. Libyan rebels who fought the Qaddafi regime reportedly were critical in  founding a “Muhajireen Brigade” in Latakia comprised entirely of foreign fighters—and  indeed, mostly of Libyans. Available evidence suggests that the group has also  welcomed fighters from Chechnya, China, and Australia—among other countries—in  recent months. ..."