An accurate representation of the Dust Hill prototype

Now, I was wondering this for a long time - can you accurately recreate sprites/tiles from these low-res mockups? One of the bigger ones was Dust Hill, a Zone originally planned for Sonic 2 but scrapped due to time limits. And now, I know, there is a hack (multiple, I believe) that somewhat accurately recreates it. But after comparing it with the mockup, I have found some inaccuracies. So I couldn't help myself but ask this question - is there a way to figure out what palette the original mockup - or prototype of Dust Hill used? Is there a good way to trace the pixels? I've already tried it once, and I managed to figure out which one of the Sonic sprite the picture used, but not much aside from that. I'm more of a spriter and I'm all about design and art direction, so I would be pleased to find out if there is a way to somewhat closely learn what it originally looked like.

Here's two pictures of the mockups that I believe are the highest resolution ones around. I think that the brighter one is the most believable as the colours match Sonic's initial sprite in Sonic 2 the most of the two.

 

Last year or so, Tom Payne dropped some art disks he had for Sonic 2, which contains the original art of that alligator enemy.

That should provide a point of reference of what palette line 2 looked like.

 

Thanks for that. It's hopefully some sort of hint as to the colour scale, and probably clears up what the cacti's palettes were(?)