I wouldn't be jumping to believe that just yet unless Mirarchi stabbed Desjardins in the back there is no way he would let Sollecito/Rizzuto murder Raynald because him and Mirarchi are so close. If they decided to work with Mirarchi he had to give up Ray I think IMHO.
I would not rule out Mirarchi stabbing Desjardins in the back either. He was very close to him, but it's not like they're bound by blood. Remember that Raynald was once close to Vito too, and that did not stop him from double crossing the family and working with the enemy.
If Mirarchi is with the Rizzutos now, it's because he sees it as an opportunity to save his own butt from all these assassinations, and because he can position himself to be something significant in the organization.
