Advice needed please

We do not have diesel models in US. So no information engine/transmission wise on it. I could not pull up either document to read.

After reading the reports it looks like what I would consider to be normal wear and corrosion for that mileage if used in most areas that get snow or humidity/rain, especially if you are near saltwater. Sadly most cars are made to a price point and the Yaris is no exception.
What I would likely do would be to replace the split bushings and then scrub off any rust crud that you can with a wire wheel/wire brush. Spray on some rust stop paint and coat it with WaxOyl. That should buy you some years. If you have actual rust holes they could be repaired.
If you were in the area I'm in you would REALLY scream. I have had vehicles that were two years old with rust under them from the salt and spray they use on the roads and those are cars that were $30-$40,000.00 new.