Well Fangio was daredevil he used to pull stunts that no one could imagine at that time. He used to drive like he had nothing to loose and hence his death in the car. He was the 1st to drift with the tail out manuvers.
As for ferrari being improved by Schumy well, if it was not for the benetton team Schumy would not have been where he is today. But yes he did give feed back to the unwinninf ferrari team but remember ferrari has big Fanship which means cash for FIA. And inturn Ferrari was alloed to bend the rules in their favor all the time. So if FIA would not have done so, ferrari or schumy would not have been togather for so long. Schmy was offered more money by other teams but he never wanted to change coz he knew he could not win with the other teams like he can with Ferrari.