Finally got around to surgery last night. I'll leave my solution here for posterity, because someone out there is going to experience the same WTF moments.
The bolt in question is just behind the plastic edge that the rubber "mud flap" protecting the rear shock mounts to. This flap is held in place by three pop rivets. I removed the left and center rivet, and pushed it out of the way:
[image: IMG_0101.thumb.jpg.2e8b90f30824344a873ae1d85e36aa13.jpg]
[image: IMG_0102.thumb.jpg.6ac210446b6ba3fed9522cd7187215b0.jpg]
Next, I used tin snips and a cutting wheel on my Dremel to cut a small access to get to the 10mm bolt:
[image: IMG_0103.thumb.jpg.8522c9e227220535e3d6e7da766fbfa7.jpg]
Now I could get a 10mm six point socket completely on it and break it free. From there, I could move the junction block with the flare nut free of the intruding bracket, get a flare nut wrench on it, and break that part free as well. No other way to really get this flare nut free without breaking that bracket bolt first, so if yours is seized, you are going to disassemble the rear of the bike or do surgery like I did. I can't stress this enough, that flare nut is really soft and will round right away if you try to turn it without freeing it of this bracket first, so you can fully seat the flare nut wrench.
Something, something, something later, now it looks like this. All of my brake lines are in place and torqued down. I zip tied the Galfer hoses through the hole where the old junction was (couldn't reuse anything, and Galfer didn't supply anything interesting to hold it in place). Yes, it's ugly, but no one is going to see it. I'll rivet the flap back in place after I see nothing is leaking. The flap will completely cover the access cut I made.
[image: IMG_0106.thumb.jpg.65cef06077ef866ceb15c947f94e517b.jpg]
I also installed a new chain guard that I already used Cerakote trim wipes on, plus some new hose clamps. I've seen people use different ways of securing the smaller diameter Galfer lines to different chain guards. I used some 1/8" rubber sheet in red, cut some strips, and stuffed them in the clamps with the hoses like so:
[image: IMG_0105.thumb.jpg.bf77e050a51f9c7d5a8c148e3e95df73.jpg]
[image: IMG_0104.thumb.jpg.e5d689f5ae4ac713e0ca47dc0791cecb.jpg]
Hopefully, will get to take a stab at filling the brake system tomorrow. The one hitch I see for solo bleeding is the Galfer bolt/bleeder valve for the proportioning valve (high point under the seat) is something smaller than the M8 used everywhere else. So I have Speed Bleeders everywhere except of course the place that is going to be the biggest PITA, where it would help the most for bleeding sans help. I could just reinstall the original Honda part but it has a fair amount of rust in it, and I'd have to clean it.