Sure looks like the spring, if available, will just slip back in (after general cleaning and considering the other two springs' remaining life). But likely the springs are specific to the manufacturer, design series and possibly model and won't be stocked by a LBS. Have you tried contacting Superteam? I suppose someone could craft a replacement spring, not my skill set.

Is the springless pawl the cause of the coasting and back pedaling problems? I doubt that but the broken spring bits, possibly moving into a position that might jam the free hub body, this I could see.

To my eyes I see interesting marks on the pawl spring retaining "shoulder", axial and about what i would think are the spacing of the ratchet ring's teeth. I suspect that the pawl wasn't engaging and this forces the FHB off axis when pedaling hard, forcing the ring's teeth into the shoulder. How this would affect coasting or backpedaling is something I'll have to think on. But besides the pawl spring I would look for other wear or loose fittings as the two might not be connected, although logic would suggest they are. Andy