Mike Verta has talked about this kind of thing before. According to him, scanning Technicolor prints is possible, but getting any kind of usable result requires the latest and greatest in scanning equipment, and that sure as hell ain't cheap. The high contrast of the prints is such that duplicating them using traditional methods is impossible.

As far as colour is concerned, provided they are stored properly they will never fade, and therefore make excellent references. The dye matrix master was made directly from the negative and thus the Tech prints are one generation closer to the source than regular 35mm, potentially yielding higher detail (though they're still fairly soft—the high contrast makes them look somewhat sharper than they actually are). Because of the way they were made, no two have exactly the same colour balance, although they are pretty close to each other on the whole. Extreme deviations may occasionally appear on a few of the prints, but these are due to human error in the lab and should not be considered representative of the film's true look. There is a possibility that the colour timing isn't exactly the same as it was for standard 35mm anyway, since going from the negative and not the existing interpositive means it would have had to be done over again, but presumably they got it close enough not to worry overmuch about this.

The different colour balance inherent in 70's projection bulbs means that putting it through a neutral light source will yield inaccuracy. This must be compensated for to get a meaningful result, or else the image won't show enough of the warmth it was intended to have.

And yes, unfortunately they all seem to have had their first reel hacked off and replaced with Eastman versions containing the Episode IV crawl, so there just isn't as good a version out there of the film's beginning as there ought to be.