The deflection pulley falls off somtimes from the bearing seizing. Also, when replaceing the tensioner you might as well do the other as it will most likely fails soon after. The new hydraulic tensioner fixes the squeal caused by the mechanical tensioner, but you must remember the squeaks can come from multiple spots...Tensioner, Deflection pulley, alternator... Using along screwdriver and being very careful it is easy to diagnose these parts.
As far as the fan not coming off, there is a tool that holds the water pump pulley in place and the fan is easier to remove..in the case of the fan, it is righty loosy lefty tighty... reverse thread.