Don't know about your Jazz, but just as food for thought I recently got a used Yaris which was a bit "frilly round the edges" underneath so i spent some time cleaning up, de-rusting and priming/painting, including the front suspension arms and the hub areas with brake splash shields.
The shields were fixed with hex head bolts with sockets (I think Torx). I removed them using the hex, I doubt the socket would have held up, but they came out no issue. The shields had a round hole in the middle so couldn't be removed with the driveshafts/hubs in place, but I remember thinking that you could simply cut out the thin section in the shield where the caliper sits and remove old ones and fit new ones without disturbing the hubs. The fixing points would offer enough support without the thin section in place and would be better than nothing.
Aygos (etc) don't have these shields and they suffer badly from corrosion on the inner disc face especially if not in daily use.