I think it was left to Casso and Amuso to decide between themselves, and Casso chose to be Consigliere and let Vic be the boss. Then, if I'm not mistaken, Casso would become Underboss and Frank Lastorino briefly became Consigliere.

I think it was Casso's position if he wanted it, but for whatever reason he didn't.

Goes to show it's just a title. He still had all the power that came with being a boss.

I invoke my right under the 5th amendment of the United States constitution and decline to answer the question.