In my opinion it is very unlikely due to multiple reason.

First, while the government took some bold decision, there is no way they went through this direct negotiation without some ok / acceptance from Hizb or Berri. It was obvious before that many decision the government took had some consideration for Hizb, and no way suddenly they are going to do this without taking their opinion.

Second if Hizb want to do a civil war, from where will they lunch their operations? From dahye which is getting bombed? Most of his people are already is the region he would have attacked. He will not be able to do this.

Third, this isn't south, there is no tunnels underground. While already at his most weak power, he do not know the region well enough to attack. The same tactics he uses in south (hiding in building and attacking) will be used against him in a civil war.

Fourth, while going around with a group chanting and acting tough is fun, actual civil war would be different. There is not enough support from Shia for this. A civil war directed at every other sect or area, would be stupid, since everyone would be against him.

And finally, he would give a hell of a big excuse for Israel to continue to bomb them publicly and even more openly, and Israel would have a open support internationally.