The other issue here is CGI special effects.
While Ghosts was probably shot on film and so the source film reels (if they still exists) could theoretically be scanned in at 4K resolution, the special effects (skeleton etc) would probably look horrific on modern displays in their original form.
It depends. The visual effects in Michael's music videos such as Black or White/Scream (for example) would need to be redone as their final output would be tape and therefore at standard definition. So those would look terrible in HD in their current state as they'd be upscaled, however Ghosts was shown at Cannes on film, so the visual effects would have been rendered at a resolution suitable for 35mm, and there is high definition and thus wouldn't need to be upscaled. I'm talking about this from a technical point of view mostly.
Like sure, artistically they're absolutely nowhere near as detailed as today's CGI of course, but they don't need to be. Nobody expects a 1996 film to have 2017 CGI anyway and its still watchable. It's basically the same situation as say, Star Wars Episode I: The Phantom Menace or any other late 90s film with CGI. Shot on film, has 90s CGI that was rendered at said high resolution and then output to film as well
So assuming MJ's short films were shot on film and stored well over the last 20 - 30 years, then the MJ Estate would need to find the unedited film source material, rescan them and edit them, and also produce new special effects at 4K resolution. It's like starting from scratch and it'll be expensive, even for videos with no special effects at all (e.g. They Don't Care About Us - Brazil Version).
Perhaps we could tell by looking at the various "making of" videos that were played on MTV in the 90s which MJ short films were originally shot on film but that won't help us if the Estate cannot find the original source film and if they don't want to spend money converting them.
Indeed, it's quite a project. If they still have the EDL's lying around however, it should definitely help quicken up the process when they're editing the original negatives. I do worry if they even have access to the original negatives and I would love to see Michael's films in high definition... it's evidential they have access to a number of negatives, just look at what we got in Bad 25.
It really is an issue of cost versus return, like you said this project is going to be very expensive. There's no winning too, if they only did some eras at first (a much more cost effective approach to test the waters), fans would complain they hadn't done the rest or even wait for a complete boxset, but if they do all of his music videos at once... it can be a rather risky project for them financially.
Thankfully the VFX issue only really effects his music videos from Dangerous-era onwards. I think your earlier question of updating the VFX actually comes into play for these short films, since they're going to be re-rendered anyway. I don't see much point in spending the money to re-do Ghosts' VFX... but if we're already re-rendering the spaceship in Scream to be at a higher resolution, do we go in and update those to modern day standards? Decisions, decisions.
