Regarding item 1, as others have stated you do not need to remove the rear sight to take out the striker. You do need to remove it if you want to remove the spring for the firing pin block.

I sometimes like to occasionally remove the striker and make sure there is no accumulated gunk on it or the channel that could cause a light strike. But I have never felt the need to remove the firing pin block. That last step goes from borderline OCD to full blown OCD.