[Gumby Bush]

Viking Orcs sound wonderful. Beware the sea orcs! (raiding and pillaging is the stereotype in both cases, right?)

I look at goblins, see "green skin" and drop them in a jungle. Kobolds, if blue, should live by the sea or something IMHO. But whatever floats your boat.

Of course minotaurs are herbivorous when used as a PC-race! (Mine are cowherd-nomads. They aren't vegan and are known for their cheeses prepared in magic pottery)

I've always assumed Germanic, Jewish, or Russian dwarves, on account of how I imagine their language. Not living underground is a bit odd, I suppose. I mean, if you're going to be mining out caves to build towers, might as well use the massive basement, right? But I also have dwarven shepherds living on the surface (which is also part of why I imagine them Jewish: I wanted a dwarven cleric, imagined him similar to Old Testament prophets, and away we went).

So long as the variations are a result of thinking out how a race might reasonably be, I would be fine with any variation. So, as long as you can explain the color-variations of your dragons independently of racial variations, I would be happy with it, but as a player I would ask the question.

Spitballing on dragon color: I would guess atmospheric compositions might have an effect, or some dragons might be colored in a manner so as to camouflage them better where they hunt. So either you would be able to tell the region of origin, the likely hunting grounds/tactics (A white dragon! Either from up north, or one of those dragons that sticks to the clouds...).

One should, of course, make sure players are aware of many of these divergences before play begins, and it sounds like you may want to ease players into it. Maybe start classic D&D-style and let the sea orcs raid a coastal village. If you can get your players to spontaneously think of tactics their enemies might be good at, so that they say "oh, these traits of kobolds would also work in a jungle!" that may help, too. It requires them to think at a more strategic level, though ("how do these kobolds actually operate?" rather than just "kobold? I attack!").