I disagree on (c). I think the ball was further down the field when it was first caught -- over and behind the receiver's head, then when he was tackled. Line judge was standing right there. Not saying I disagree that the spot was probably wrong, just that it shouldn't have been reversed.
On (d), this seems to be a recurring and misunderstand situation in football all year. If the receiver, in the process of catching the ball, is hit and ultimately tackled, he must maintain possession all the way to the ground if (but only if) he is tackled by the player that hit him as the ball arrived. If the hit occurs after the catch, not simultaneous or nearly simultaneous with it, the receiver must only make a "football move" to establish possession.There was an interesting example of this in the earlier game today, where the player was hit as he caught the ball, but then hit by a second defender who dislodged the ball. There it's a fumble too.