This isn't about hours - in the uk BA (when they are actualy flying and not on strike) hire many many cadets with 250 hrs and have done so for many years. There is a diferance in emphasis between the US and UK with the US traditionaly requiring higher hours.
The problem lies with relevant experiance, training and work paterns.
Redflyer - I suspect we may work for the same company. You are correct + 15kt for flap 35. The increase of 20kt is for V ref flap 5, flap 10 and flap 15.
They should have had as a minimum speed vref flap 5 + 20kt for ice and + 10kt for manouver. This would have alowed them up to 30' AOB.
As to reducing power when gear was selected it makes sense if you consider that he wanted to be at Vref flap 15 and was therefore wanting the speed to decrease.
As you corectly point out stick shake went off as designed before the flaps actually travelled to 15.