Eusebio's alternative career

In 1957, Juventus discovered Eusebio when he was 15 years. Eusebio's mother did not want his son to move to Italy. I don't know the Italian law in 1957. He was not an oriundo. Let's assume that he became an Italian citizen around 1962. What would happen?

-- Would the Italians select a Black player to their national team in 1960's?
-- Italy with Riveria, Mozzola, Facchetti, Zoff, Riva and Eusebio?
-- Serie A banned foreign players by 1964.

In 1960, Eusebio was discovered by Bauer who wanted him to join Sao Paulo, but Sao Paulo rejected him. What if he went to Brazil? Again, I do not know Brazilian law in 1960. In 2015, he could become a Brazilian citizen in 4 years. He would have been eligible to play for Brazil by 1964.

-- I don't know if Brazil ever capped a foreign-born player before. And I don't know if Brazil would cap a foreign-born player in 1964.
-- Brazil with Garrincha, Pele, Eusebio?
-- Can Brazil win the WC in 1966 with Eusebio? Imagine Brazil with Eusebio in 1970.

They could have been teammates in 1966.

Please also see my All-Time World Cup Team Index.