How bent are the forks? If there's a kink, they can't be fixed. If there's just a small smooth bend, repair might be possible. You'd want to put it on V blocks in a press, and rotate it with a dial indicator against it to measure runout. The pics show enough bend that I doubt they can be repaired, though.
The steering stem is the part that connects the two triple clamps, I think it's more likely that the lower clamp is bent but they aren't sold separately. Depending on how bent it is, repair may or may not be possible.
Both the header and the muffler are damaged? The header is so expensive because it has a catalytic converter in it, but I see used ones on eBay fairly cheap ($100 for the header + slip on but not sure if they're willing to ship to you). However, I don't see any damage in your pics that would worry me.