To be honest, I think he was doing well in Italy and always had potential, but wasn't hyped, that why Sporting got him and not Juve, Roma, Napoli, Inter, Milan, etc… those teams buy everything that is hyped nowadays, either good or not.
I never got impressed with Soler, the very few times that i saw him play, so I would rule him out. Ceballos is not on Bruno Fernande level yet. It would be about personal preference between Ruiz and Fernandes, if you want a more ofensive player go for Fernandes, if you want a more defensive player go for Ruiz.
By the way, I think Fernandes would do very well in a Top team, the problem is the club he plays for is asking too much for him.