I would sell Pepe and buy Hummels because he is a much better player. Also, I'd buy another world class player to rotate with Isco because Isco is a wonderkid himself so there is not much need in getting another one unless you're planning on changing formation so you can accommodate for 2 world...
This happens in game too, not just on the menu where you choose which team you want to be. Also, only happens for teams that have not got their proper kits on the game. Oh yeah, and I do not know how to download kit/badge packs for Mac so any help would be appreciated