MMe wrote:e.g. Whats the difference about Emerald and Emerald Green?
Actually, there isn't any difference in that case. (Aren't those on two different sets of the tables? the first set preserves the Golden Dawn originals, which were based on Windsor Newton London watercolors that haven't changed their formulae in over a century, and were the exact colors used by Moina Mathers - so we know what she intended. The second set of tables was provided to state the colors more precisely in more modern language.)
What kind of color is Blue emerald green? And Sea Green?
The use of "Sea Green" originally meant "the color called Sea Green in the commercial water color product by Windsor Newton, London formulation." - Generally, though, you can get these from a dictionary. "Sea Green" is a clear, light, bluish-green: I'd call it green-blue-green (i.e., the green side of blue-green, halfway between green and blue-green). "Emerald green" was used in those color labels to mean the purest intense mid-tone color of green, and "blue emerald green" means you add a little blue to this.
Can you tell me some reference about the color?
See above.
can get the HEX or RGB code of the colors listed in the eight charts (201-208)?
No idea. Nobody has compiled it. A pure red doesn't even exist in RGB (the "full red" in RGB is slightly too orangish, and there is the added problem that the output medium - what screen you're using, and what video card - affects how these look.
The following might be useful to you - it's not quite right because of the exact RGB problems, but it was my best effort a few years ago. Here are King scale colors of the 22 Paths (Mothers above Doubles above Simples):
http://aumha.org/arcane/pastos.htm