Brakes - Arrrrrgggggghhhh.
Thanks to all for your comments. A summary would be that it's a simple repair but pay attention and do it right - & there's nothing wrong with installing new magnets.
Oh! By the way - I found the broken wires while wrapping-up my first DIY complete annual brake inspection and bearing repack. A good friend and great mechanic offered to teach me how to do the job correctly. By the time I got to the last two wheels I was on my own with help available if requested. It was a mixed business to find the broken wires but the bearing repack was great - no unwanted heat on the hubs after a test drive.
First reaction - "Arrrrggggghhhh. Now the job won't be done today."
Second reaction - "Pretty cool - I wonder if a shop would have found this?"
It looks like the various shops in our area are the usual mixed bag of competence and helpfulness. One offered to sell me a brake assembly or a magnet. Two others gave me chunks of brake wiring harness. My practice is to buy something useful if a shop gives me a small item. A chunk of wiring harness equaled a tube of Sikaflex.
Speed is Life . . . guidance is optional . . .
The Traveling Circus: 2013 Flying Cloud 30A; 2006 Chevy Duramax Crew/LWB
Air #42313 TAC VA-7 WBCCI #1290