The first two pictures are of what we refer to as the "bolt lift kit." It's basically the case head from a .38 Spl with a detent ball in the primer pocket, and it's inserted into the rear of the bolt assembly just under the BAS (bolt assembly screw). The BAS also has to be shortened slightly to accommodate this mod. The principle at work is that the detent ball offers up less friction against the face of the BAS due to a much smaller area of contact and thus helps lighten bolt lift. It's a DIY thing that's been well covered on this site over the years.

That last picture appears to be a broken adjustment nut fort he firing pin assembly. If you look at the photo in the following link it's sandwiched between the firing pin spring and the cocking piece. It's used to adjust the firing pin protrusion.

http://www.savageshooters.com/content.php?167-Savage-110-Bolt-Assembly-Parts

I'm not aware of any changes to this part over the years, but I'm not sure if Savage would sell that part separate or not. I don't think it's something that Brownells or MidwayUSA carries. Maybe try Numrich's as they could have one from a parts gun they bought.