Arguably, Cicci wasn't as big an offender to Michael as Frankie was--Cicci said he never got a direct order from Michael. But Cicci violated omerta and damaged Michael by identifying him as the head of the family. That was before the Witness Protection Program. Cicci probably was assigned his own cell, or prison suite, in a Federal pen, as was Joe Valachi. Michael might have been able to have gotten to him, but I'm guessing that, after getting rid of Pentangeli and Roth, he might have determined that Cicci wasn't important enough to deal with.

The Rosatos were "on the run." They could have been a danger to Michael, but I'm guessing that, because they were involved in a shootout with the cops, and wounded or killed at least one, Michael may have found it prudent to let the NYC cops take care of the Rosatos.

As for NYC: A major question is, who succeeded Pentangeli as head of the Olive Oil Business? Probably not Zasa--he looked too young in 1979, in Part III, to have been a major player in late 1958, when Frankie was garotted and turned rat. While I don't think it would be in Michael's nature to simply walk away from NYC, he may have wanted to distance himself ever-farther from NYC following his close scrape with the Senate Subcommittee. That's not much of an answer, but I can't do better.