Not properly. You could change the assignTeamTournament reference to the Europa League ID, and copy the adboards for a generic assignment as well as a tournament assignment. This would have a lower precedence than any team assignments though, and may not work in all circumstances. Alternately, you could copy items as assign as a team assignment. In both cases, most things except kits would only apply if Porto play at home. For fan cards, they can be enabled in all tournaments except friendlies by editing the compdata. If you inspect tournaments in CM16, there is an option to "use fan cards" in individual stages of each tournament. I think that is the source of the problem, the game does not reload the stadium. I do not believe I can force it to do so unfortunately.