Glad it gave up for you, Chooglin.
I had my fan and motor removed from the housing so the job was in my lap.
I bought a Harbor Freight Rivet set for my door wing window seal installation for pretty cheap. There were several rivet sizes.
I don't recall how small the rivets were in the set, but I'd be willing to bet you could rivet the cage back to the hub... else you could used some small machine screws with lock washers and hex nuts. You may have to drill out the holes a little for the screws.
The fan cages on mine had a balancing weight that clipped onto one of the cage fins. After you get the hub secured again and everything assembled, you might hook the fan up and see if you can find a happy balance spot... then you'd be good to go.
Jerry
