I got myself some 3/4" cable clamps for electrical wires, and I think they'll be fine. I tried to find a way to use existing screws to hold the clamps, but the cables would have to be inside the fender where they would be more exposed to danger.
I am trying to fix things up down there so that protruding hose doesn't grab the first downed branch I drive by.
It seems like there should be some kind of fitting that would change the way that bottom hose runs so it doesn't hang out there. On the other hand, there are a couple of cables down there hanging out, right from the factory, and they have survived.
Welding to the tractor fender is a non-starter. It's very thin, and getting myself and a torch in there would not be easy anyway.