With regard to the broken control horn on the flaperon, it may not have failed with a fore/aft load but with a side load....
Very true. Keep in mind that the axis of the hinge pivots is more or less parallel with the sweep of the wing, so that a 'fore-and-aft' load would actually have a considerable lateral component. Just plugging some numbers in, with a hinge axis angle of 120 degrees to the direction of motion (30 degree wing sweep) during a ditching and a load of unity, the lateral component would be around 0.6, Also, if one end of the flaperon contacted the water first, there'd be a considerable turning moment as well.
I think. High school physics is a long way behind me, and if anyone wants to check my calculations, feel free.