The cyan color reminds me of the Maxkey cyan set, or Fluffy Clouds which I think is currently running.
One thing that I think will be confusing is the fact that the set isn't really "green", and a lot of people won't know about the movie.
Something about the fully uniform color makes me think it should have a more uniform profile, maybe 1-2-3-3-3-4. But that's obviously up to your preference.
A great lot of the posters of the movie Green Book were in this turquoise(blue-green) color, not literally pure green, even though the movie's name Green Book has the word "green". This color was from the car 1962 Cadillac Sedan DeVille in the movie. Since the keyset is inspired by the movie, the keyset follows the same convention like the posters.
In terms of colors, there are two main colors white, turquoise. I use WFK for white. It's an usual choice as snow white for SP ABS. And the code BBQ did a pretty close match to the turquoise color in the poster. Currently I use it for renders(no matter 2D or coming 3D). It's possible to switch to a customized color option for a closer match. Before GB, I usually do color matching/determination using real thing in my hands, like keycaps or color chips, these colors (including the novelties ones) would be possible to changed/tuned util then.
Seeing some pictures of Maxkey cyan, this turquoise color doesn't look quite close to it. As for Fluffy Clouds, I don't know it before. Thanks for the reminder. Fluffy Clouds used WFK and BBQ. The two main colors WFK, BBQ are the same, but I guess it would not be conflicting because Fluffy Clouds has a reversed alpha/mod theme, uniform profile, and for compatibility it only provides kits to fit Ortho layouts. Besides, Fluffy Clouds is running a GB already, ending in this June. Even if it's possible, the GB for this keyset will run months and months after SA Fluffy Clounds GB finishes. It will not affect the sale of SA Fluffy Clounds.
I'm not sure whether fully uniform color is a trend, but I do feel like I'm seeing more and more keysets in uniform colors these two years. For SA Green Book, it just simply follows the color theme of these movie posters to have a whole background of turquoise, and some white in the foreground(and for all these fonts). No intent to follow this potential uniform color trend. The profile would stick to be sculpted rather than all R3, starting with 1-1-2-3-... It's more popular to have sculpted profile nowadays.