I poked at it a bit while looking over all the available spare parts, and the chain/sprockets/shockcord seem pretty solid, the greatest wonkiness appeared to be around the cage. I looked over the axle/sprocket replacement sheet so many times I may have accidentally memorized it, but I just had the epiphany that these two rusty pieces are not supposed to be two pieces...

Does anyone know how they are supposed to be attached/have any suggestions on how best to re-attach them?