Hmmm I'm a bit too lazy right now to do any testing.
But I think, in platformer, the benefit of using physics it for objects falling or objects interacting with other physics objects.
So I think you should deactivate the physics behavior as soon as the platform character interact with it. Because the main issue with physics and platformer it the fact that platformer characters doesn't behave realistically.
platformer character and physics object are in two different world with different rules.
So deactivate physics on interaction with an non-physical object.
I you want to throw a block, reactivate the behavior the moment the object is thrown and do a "set impulse"
It may be a bit more complicated than what I just said, but the idea is to really think about what you expect to be from the physic world and from the platformer world. Pushing, Carrying, doesn't have to be physically right, but falling and bouncing should.
That was my thought :D