Great post to be sure.
As I re-assemble my bike, just last night I was dealing with the pegs, front and back like you are speaking on.
I had "file" photos of that area that I had taken to assist me in re-assembly, having the ipad handy for reminding me where stuff goes...
Great that mother-kawi gave us passenger pegs, but she over complicated the system. Some odd shi*t drops out of these if you aint ready, ask me how I know.
I was hammering my cir-clips flat last night, straightening them for re-assembly. I don't think they are brittle, it's just not bulletproof.
I was positive I had ordered new clips... but turned out I got the larger ones for the front pegs, and missed getting the ones for the passenger pegs.
I considered leaving them off.... but on the odd chance one of my riding chums breaks down and we gotta ride double to get into town, etc.,
I would have wished they were still there. There is always the smoking hot hitchhiker possibility.. in my dreams
I like the suggestion of a bolt and likely a washer and lock nut. Maybe throw the old hardware in the tool bag for a spare.