Honestly, you don't need any of it. We used towels and blankets for changing on the bed or the floor. In the newborn days, we used the changing table on the PnP, but it was worthless and couldn't hold DS's weight.
My mom gave us some multi-use pads, and those were nice since they are waterproof, but none of it is necessary.
I still change DS on the floor on a towel or one of the pads, and we'll probably just use the bed for DD (with a towel/blanket/pad).