Fed playing in Barcelona may be a fake news . The Barcelona tourney claims they don't know anything about it. It means they have not agreed for any app fee, in particular. I don't see Fed playing in Barcelona without app fee. Also, if Fed wanted to test whether Barcelona is willing to pony up the cash, he would have sent indirect feelers through his agent. He would not do like this by creating a media buzz by planting a false news in a fan's head.
So, most probably Fed will play Madrid, Rome and RG or else just Rome and RG (unless of course, suddenly Barcelona organizers want to spend a million bucks on Federer; apparently Barcelona has already agreed to play other players and so may not have enough cash left to spare).
If Fed wants app fee, he should either play in Budapest 250. I don't think Fed has every played in Hungary before. Not sure whether Hungarians have enough money to wet Fed's appetite though.