Kay… got an answer from 2chan. 
Case anyone else was wondering: there’s an official novel called [u]On the Way to a Smile[/u], written by Kazushige Nojima, that covers loose strings in the FF7 universe and is considered canon.
Basically all the Turks except for Tseng, Reno, Rude, and Elena are not under Shinra’s payroll. They were listed as dead or retired, because of some issues concerning Scarlet and Heidegger. After the fall of Shinra, the Turks were responsible for saving Rufus after the whole WEAPON incident (unlike the other company executives, they actually like him). The other Turks still maintain contact with Tseng and Rufus as “undercover” and “reserve” agents. They’re always ready to be called on, but it’s generally accepted that Tseng and Rufus only make the call when things are serious or desperate.
Only Tseng, Reno, Rude, and Elena are in active service. During Advent Children, the other Turks weren’t mobilized, because Rufus felt he had the situation under control, and Vincent saved Tseng and Elena.
Also of interesting note: individuals who physically qualify to be SOLDIER (via skill and attributes), but lack the mental discipline (former criminals, rebels against authority), become Turks. So before the whole Mako infusion process, Turks are equal to SOLDIER candidates. There’s also was an academy for Turks training… so they’re probably quite a lot of them. Shinra’s version of the CIA and FBI, more or less. There’s also a Turk who supposedly is on Sephiroth and Genesis level: they called him the God of Death. He’s one of the “semiretired” agents though…
