FC Barcelona is not at his best, financially speaking, and can't afford to get new players (even if it doesn't seem like they need it either). This can be a good opportunity for Real Madrid to catch up, although I'm not sure about who should they get among the players you mention. What is clear is that given their performance in La Liga, the worst option would be not to catch anyone.
The transfer window is already closed and of course Madrid wouldn't get anyone to improve their current performance until the end of season. It will be a big challenge for Ancelotti to use his current squad and try to make his players not get injured easily. But Madrid needs to bring a new player in needed position such as forward and full back.
Cavajal the Spanish player is due for sitting on the bench and making use of younger players to help with the squad, Real Madrid once wanted James of Real Madrid but talks of his dropped immediately he said he's not interested in leaving Chelsea. That spot need replacement and also midfielder's and Benzema. I heard Real Madrid signed a young Brazilian as the replacement for Benzema true?
Some good midfielder's should also arrive else Real Madrid can't fight for the league next season. The earlier they get the job done, tue better for them