The post you are replying to was made on July 6. SAG-AFTRA went on strike on July 14. It's entirely possible that plans have changed since that original announcement, in light of the strike.
JMS posted in a facebook comment a few days ago that the cast wouldn't be promoting
The Road Home because of the strike, however, he wrote it under an Animation Guild contract, not a Writer's Guild contract, so he can promote it since he's not on strike as an animation writer, just as a live-action film/TV writer (I'm not sure if the definition of "struck work" includes long-completed projects, though it seems to, so it's entirely possible he's going to be in a situation where he, say, can't talk about the original Babylon 5 series on a panel about TRH).
Were the VFX remastered for an HD release?
Nope.
On Facebook, Mojo Leibowitz from the original VFX team mentioned he'd heard a rumor that the VFX had been upscaled, but he doesn't think it's likely. The story about this release is that, when B5 was originally being made, conformed film edits were created for each episode for overseas markets that didn't have satellite uplinks and digital tape systems, and the HD version was made from scanning those film copies. So, most likely, VFX shots (as well as crossfades, shots with subtitles, and miscellaneous other shots that had some kind of post-production process on them, probably including reused footage from other episodes in recaps and flashbacks, based on the DVDs) will just be the SD versions, printed on to film, then rescanned digitally. At best, those shots would've been either downsampled from the scan back to SD or sourced from the digital video masters, and then upscaled with some modern machine-learning method.
Either way, though, there's probably still going to be a noticeable quality shift in composite shots, either they'll be softer (and possibly even with some visible pixelation sometimes) than the surrounding footage, or they'll have weird upscale-smoothness. Not as noticeable as on the DVDs, though, since the framing won't shift, and there was also a lot of weird stuff there with the widescreen master having originally been done for European releases, so it was converted from 24 frames a second to 30 to 50 then back to 24 for the DVDs.
I'd rather have a ground-up remaster, TNG-style, but even the most popular Star Trek show couldn't make that worth the time and effort, so that's unlikely to ever happen. It might actually be easier to build a time machine and get the post-production suite the damn widescreen mastering monitor in 1993 so they could've produced DVD-quality widescreen episodes from the start in parallel to the 4x3 version, like Stargate SG-1 did.
