these are the colors i've come up with. the low quality scans themselves aren't too much of a problem aside from their lack of definition? the left is the original scan, the middle is one i redew, and the right is one i darkened. i think redrawing brings out the most definition, but it is also the most expensive and time consuming option to bring back some of the definition in the scan. the darkened scan looks a little more defined, but the darkening itself can be kind of messy.

this one i just darkened but you can kinda see what i mean where it goes a little low def?