Edit: just had a look at some clips from youtube and it looks like the fullscreen version is open matte.
I watched that bit of the documentary and I think it confirms how I interpreted the script, so I turned down the colour on my TV and watched the Time Warp in black and white, it looks good, probably because the set was designed to be black and white, but I'm not sure how effective the colour transition on Frank's face would be his lips are such a dark red I'm not sure it would have the right impact but it's worth a try, the only reason I can think that they didn't have the technology to do it is because this was a very low budget flm and they couldn't afford to try. The easter egg doesn't make much sense but the transition works well and I'm sure it would have been done with the consent of the film makers.
I think for myself I might do a few versions and see which I like:
1. Red lips at the begining fade over the black and white church scene, colour comes in during the Time Warp, whole thing in wide screen, this wouldn't be much work as it only involves fiddling with the lips fading everything else is already on the DVD.
2. As scritped, red curtains open up onto the Fox Logo in 4:3 in black and white then the clips from the films as mentioned in the script with new credits in between also in black and white, this would then run straight into the church scene (minus the opening few shots which include the lips) still in 4:3 then switch to widescreen during time warp and full colour on frank's face.
3. Another option (admittedly of my own invention) is to have have black and white up to frank's face, then use some trickery so that his lips are the only colour until he walks away and when his back blocks the whole screen as he walks into the ballroom it revert to the normal colour, then again you get a great look of shock from brad and janet directly after the transition.
Since these all only affect the first 20ish min of the film they could all be put on one disc with an option to chose between them, or two options one for the titles one for the colour transition, although the ability to do that is currently beyond me.
the other thing I would want to do is reinsert the Once in a while scene cutting it back together as scripted with the pink shots of Janet making her way to the lab and ending before the 'if only' scene and Janet Seeing Brad on the monitor. Does the US version have this scene in the Film? if so when does it take place?
loads to think about, I might rip the DVD to my hard drive this evening and start playing.