Yes, Portugal is a definite threat. And they will feel somewhat at home in Brazil where Portuguese is the official language. They should get some good crowd support in the early rounds.
Spain’s team, like Germany’s, is still young enough; they were beaten by Brazil in Brazil. As an American that watched the US dismantle Portugal in World Cup play, I don’t see them having a chance; like the US, they’ll be lucky to advance from the first round.
Time will tell.