Why wouldn't they be allowed to buy De Jong? Player wanted to come and their net expenditures remain well within FFP.
Griezmann they were going to buy last season and now they will exercise a buy option that any club could do as well. Player wants to come to Barcelona and was willing to considerably lower his wages to facilitate the move.
De Ligt is not a done deal. Only an agreement has been made, nothing signed. If he opts for more money, he won't be signed since the biggest hurdle in his acquisition is the salary and commission to Raiola - not the transfer fee.
Neymar hasn't gone anywhere yet and if he were to return to Barcelona, players would have to go back in the other direction - he too would have to accept a significantly less salary to make it happen, among other things.
RM have spent quite a bit of money but they also have plenty of assets to balance the books, especially since they are better than Barcelona in terms of selling. They need to make a splash since they finished 3rd and won nothing
Barcelona & fans are bitter about Garcia only because he is Catalan, repped by Puyol and left the club. It's mitigated by the fact that he goes to City (aka Barca-lite) and will likely see regular 1st team football sooner than he would've at Barcelona. Particularly when you consider the talent drain at La Masia over the past few years that highlights the erosion of the sporting direction & philosophy of the Catalan club