For now I think there is a possibility of Lewandowski joining Barcelona if De Jong is finally sold. Manchester United still seem so interested in the midfielder that they will try to convince Barcelona to let him go in order to reunite with his former boss at Manchester United.
I can confirm that Aubameyang and Adama are two important players who have ushered in the success of Xavi's first season with Barcelona. Adama contributed well with the speed and accuracy of his passing, while Aubameyang proved it by scoring important goals in big match. Both of these players are important for Barcelona, but Lewandowski will be something that makes the team even better.
Maybe so, but I'm a bit skeptical about Lewandowski. He is a good striker, but being a good striker in Bayern is one thing, and showing such good results in other teams may not be as easy as it seems, Messi can be an example of this. I think Lewandowski is holding a grudge against the club because they didn't want to raise his salary so he decided to leave and for now he really thinks he can score so many goals in any league.