Some updates!
I drove the car a couple times now for various errands and stuff. And am loving it. I did recently get it plated (though it's the il extended antique so not "year round"), so it's been fun to drive around. I have not yet fixed the fuel tank routing issues, so it's running on just the one tank which is ok but I do need to get that fixed.
Hoping to let the wife take it to work one day this week too.
For the fun stuff - parts! I found "everyday xj" a guy who parts out old jags (specifically xj's) and he had some of the parts I needed and a few I wanted too. Arrived Friday, like $118 total including shipping:
That's a factory battery hold down, two factory battery hold down screws (more on that later), a new taillight lens, fusebox cover, and an original radio and car side harnesses. I wanted the radio because I want my interior to look like a jag, not the back of a 1990s best buy. The radio is from an 85, so it lacks the security features (code and removable faceplate) that came around in 86 and 87. But it looks way more original and supposedly still works. Sweet!
Taillight lens was a quick swap - in the pic I was trying to hold the old one at an angle so the cracks were visible.