Just an update about the rear mudguard.
I had the same problem yesterday: the upper bolt began to budge and started to scratching the tire, and, as a consequence, the mudguard got loose, touching the tire. I was angry and found a simple, but effective solution: a double-sided tape replacing the upper bolt. I took care choosing a tape adequate to outside conditions. As in my land there is no snow or excessive heat, I think the rear mudguard problem is solved by this hack.
My lesson learned today: if there’s a hard problem unsolved, try double-sided tape. 