The way I read that is exactly what I suspect. Sollecito is the front boss, and Rizzuto seems like the boss in the back. I believe Leonardo is an educated lawyer, it's likely he will be dealing with the high end white collar crime, where as Sollecito will deal with the street stuff.

That alliance with Mirarchi seems rather interesting, Vito did the same in the past with the Cotroni faction, and it looks like the new leaders are taking a page out of that book. It's very smart if everyone holds their end of the bargain, which is a good possibility if things quiet down and business goes good.