Direct answers to your questions are :
1. No, the wear on the firing pin is not normal.
2. Dry firing will not cause this sort of wear.
3. See below for details.
4. If the trigger pull is weird, it might be explained by comments on the trigger bar below.
I don't see anything terribly wrong with the Firing Pin Safety, why would you replace it? One thing I would worry about is the Firing Pin Safety Spring, because if that isn't working correctly, the FP safety may be hanging up and causing the damage you see on the firing pin.
The trigger bar is responsible for pushing the firing pin safety into the slide, out of the way of the firing pin. Please examine the hump (see photo below) on the trigger bar to see if it has any damage at all: if there is any, that could be the source of a timing problem, delaying the movement of the FP safety, and possibly damaging the firing pin. (By the way, your trigger bar may not have the "bump", I believe that showed up on the Gen4 pistols.) If there is any damage or even noticeable wear on that part, replace the trigger and trigger bar: the part number is 357 (both come as a unit).
If the trigger bar is OK, I would replace the firing pin, the FP safety spring, and then dry fire it a bit to see if there is any more evidence of damage on the firing pin. If not, I would call the problem solved. If there is still some evidence of the firing pin hitting something, we need to dig deeper.
Since I have not seen the damage that you have clearly shown on the firing pin, let's give this a day or so to percolate: other members may have seen that damage and dealt with it.