Hi guys, this was a hard one for me to find info on so I'll post up what I found.
As stated, the old pins need grinding done to them to get them to pop out. Its not too hard and took me a few minutes with a die grinder. Then there are 3 options for replacement: new pins with c-clips (don't do it), new pins with bolts, and premium new pins with bolts and and part of the metal latch.
Unlike old styles or other brands, GM welded these hinges on and there isn't even adjustability. But, to get the door off all you have to do is remove the 10mm bolt from each hinge and the one 10mm for the thing that holds the door open and then lift the door up (I did that with a cherry picker). Took me about 30 minutes with the help of my wife.