@ skridlov
Those streaks could equally be the traces of de-icing fluid which would accumulate there after the tail is sprayed. A hydraulic leak is taken seriously, and would not go unnoticed during walk-around or maintenance.
This being said, assuming sloppy maintenance would permit a leak to continue, I do not see any hydraulic failure scenario that would result in the catastrophic structural failure we are seeing.
Assuming worst case scenarios, a full deflection of the rudder would probably result in the entire VS snapping off at those speeds/altitudes, which clearly did not happen (the VS damage we see is due to ground impact). Full elevator deflection can be countered by the stab trim, which is not driven by hydraulics but by a servo/pulley system.