Update time. I've been working on this for a couple of afternoons now. Currently have everything removed from the passenger side (knuckle, UCA, LCA, coilover, outer tie rod) and everything except the LCA on the driver's side removed. I also installed a new inner tie rod on the driver's side so I can finally adjust toe; the old one's adjusting nut was seized.
To answer my original thread title's question, yes, it's probably best to remove the knuckle and hub out of the way if you're doing both UCA and LCA and you are going to have to cut your LCA bolts.
The LCA bolts on the passenger side were well stuck in the bushings, so I had to cut them out. I'm sure I'll have to do the same on the driver's side. The Diablo blade has been awesome, so far it's cut through all four LCA bolts / bushings on the passenger side, and the trapped UCA bolt on the driver's side, plus the tie rod, and it's still cutting pretty well.
Here's the existing hub assemblies in their spindles. The passenger side turns smoothly with minimal noise. The driver's side is definitely in need of replacement. There is a dry scraping feeling to it, and a knock when you pull on it.
Short video here, driver on left, passenger on right:
https://photos.app.goo.gl/bFYirm3byRBn1AUdA
I don't have a complete maintenance history from before I bought it, but I did find a reference in the previous owner's notes that the passenger hub was replaced around 72K miles. I'm at 120K miles now so it makes sense the the original hub on the driver's side is shot and the passenger at 50K miles is still good.
I received my Timken replacement hub assemblies from Rockauto. They look good, but they're quite stiff to turn... and not as smooth as I had expected.
Is it normal for replacement hubs to have quite a lot of resistance to turning? I bought two and both of them feel about the same.