These players were already 'stars' who played internationally. Only difference is the British audience now know who they are, though those who take an interest in European football must have already known who these players were. Ba was highly rated at Hoffenheim, Cisse was consistently banging the goals in for an awful Freiburg side and Cabaye was pulling the strings for and captaining the team who won Ligue 1.
Being a household name in Europe does not automatically make you a success in the Premiership. He might not have made stars out of them, but it is remarkable how fast they all have acclimatised to the English style.