Not knowing the width of the shed and therefore the length of the floor joists it may need some central support to stop springing anyway. The pier would not be part of the wall, just isolated within the supporting wall joists. So no transmitted vibratiion.
Would you need a permit to do the work ?
What's the roof pitch angle ?
Real work would have to be a very big 'cube' of rebo'd concrete to stabilise the pier column buried into the ground beneath it.
Start digging ...
