As nine9d stated, my Platy is also very active, despite what a lot of other folks post about thep.
As far as color goes, mine has molted 4 times in under a year, and he shifts dramatically between greens,cream and pink/purple, depending on what I add/subtract from the tank. I would dub this a highly variable species,color-wise (Within a range,hey still maintain that amazing shell pattern). By this, i mean that (Unless it is bleached out white from exposure to lights at the LFS,as mentioned early in your post), you can get some dramatic coloring out of a G. platysoma.
Mine seems to prefer hermit crabs to snails, although he will eats snails if there are no hermits available. They can be picky eaters when it comes to frozen (thawed0 food. Mine (Glaurung) seems to like scallops, but he's not so hot on thawed shrimp or squid.
-Ron