LOSC fans are friendly, so I think you should not have problems in the stadium if you are next to. Obviously it depends on your behaviour...Don't be too proud or mocking if you win, then they will react
Maybe you should avoid North, level 0, with the most active people, because a group of people is always more stupid than people one by one...
I was in the stadium at the game against Porto (qualifications for Champions league), and there was lots of Portuguese at different places, I have not heard about any problem despite they won.
What I can see on your forum and our forum is you look friendly, so I think it can be a friendly game, and everybody could drink a beer at the end in front of the stadium