Many folks will inspect a gear and think it is all right to reuse because the gear teeth appear to be smooth, not pitted, and shinny. This isn't the case. If you were to look at a gear from an on end point of view, the gear tooth surface from apex to the bottom of the v, are NOT straight surfaces, The gear tooth profile from apex to bottom of the V, kinda should have a bump in the surface. So the line from apex to the bottom of the v is actually curved and then kinda straight. so the line from apex to v is rounded not straight. This is so that when two teeth mesh, in operation, they roll against each other rather then the teeth being flat to flat against each other. I don't know if i am describing this well, but if you look at your new gear, from an on end point of view, you will see the non flat gear teeth profile as they should be. Even a couple of teeth, on one gear, that are worn straight will cause spalling, over time, when reused. The flatter the surface and the amount of teeth like that on one gear, the quicker the spalling will happen. When I was working and at the airshows. I had a couple of gears on the demo table with a tag on the saying "would you reuse these?" Folks would pick then up and examine them and after a while, ask if you needed a magnifying glass to see the defects or if they were cracked and it only showed with magna flux etc. Because, they couldn't see anything wrong visually. Then I would show them a proper gear tooth profile and point out the hump on the surface and tell them to re-examine. They would all be astonished that a gear tooth could look so good but be so worn. I remember, I actually had one guy tell me he was going to go home and take the rear case of his, self-overhauled engine, that wasn't installed yet, to reinspect all the gears. Never heard from him how he made out, but he was adamant that the 5 mins. we spent to together, was awakening. Anyway, that might explain your rapid wear on the teeth.
The problem at the gear cam...I don't know, It almost looks like the pin was hard against the cam all the time. Was the pin in upside down? the head should be toward the pump arm not the cam. Don't know if that would be an issue but maybe??? Is the pin super free to move in it's slot in the accessory housing? Never saw wear like that with signs on heat on the cam before. Maybe the pump was some how pushing the pin against the cam harder then ususal all the time. That could cause the heat signature as well as the wear. Or maybe it was just super pitted there but not anywhere else. One thought, while the engine was waiting to be run, was it a long time and did you constantly turn the engine over by hand, thinking you were re-oiling everything inside but in reality, you were wiping all the oil off things inside. If you did that alot, over a long period of time, maybe that allowed the corrosion? Just a few thoughts to consider.....
Good Luck,
Mahlon