None of this is up to the terrorists at all.
It is completely clear what Russia and Turkey will do to clear the zone of terrorists. They will both force any such entities from the area. They will first simply tell them to leave or else. If they don't leave, they will be driven out militarily. It's not complicated. Frankly, the terrorists wouldn't stand even the tiniest chance without Turkey giving any cover at all.
Right now, Erdogan is concerned with two things. He wants the war refugees in Turkey and Europe to decrease, not increase. He also wants to establish a strong enough front line to deter any Kurdish movement across Turkey's border without Turkey's permission.
He wants both of those things with the blessing of both the US and Russia. It is doable, but he'll have to be on his best behavior to get it done. He will not be able to turn around and attack the YPG and SDF. Besides, I believe Assad and the SDF will come to some peaceful and reasonable deal that the US and Russia and Iran and Hezbollah will all accept. Even Israel will begrudgingly accept it all.
Putin's objective has always been totally clear. He wants regional stability reestablished with a strong Russian indicator that Russia will not allow any terrorist buildup anywhere that will threaten Russia, Russia being so close to the area.
If Trump has any brains on the matter, he will listen to Putin and dismiss the neocon noise in the US.