Best decision was Xavi because bringing him to Camp Nou was best from the management and after this Robert Lewandowski give them best double which give them win and now things could be interesting for the next season and as we have rumours about Messi which are no clear things can go more aggressive.
Now if they are able to hold things in positive way then surely we can expect good success because right now financial situation is not good they can improve this and have better success as well most chances they will be able to bring Aubameyang because Chelsea already announces about him and Barcelona can afford him as well this could be good for them and give strength to their attack as well.
At this point the fate of Messi isn't so clear if he will leave PSG at the end of the season, and join Barcelona. We will have to wait till the summer to know his decision and possible destination if he decides to leave. Barcelona's strategies to manage with the financial situations seem to be productive and can be applied again in the summer, bringing in Aubameyang shouldn't be much of a problem since Chelsea are also ready to dispose him at the end of the season for a reasonable fee.