I imagine the "lost years" were pretty boring for Vito. There was obviously some connection between some family in Sicily who was hiding Vito and the Abbandando family in New York. It would seem Vito was laying low,working in the grosseria, courting and marrying, and saving up enough money to get his own place and start a family. He really becomes transformed when he encounters Fanucci and begins to see his leadership potential. IMHO that is all we need to know about young Vito.

As for Genco, he seemed kind of goofy to me in GF II.How became such a brilliant consigliere?