You need to provide more information. What is the first image in your post? An attempt to modify Syosa's palette, or an attempt to imitate it?
In either case, you need to keep in mind that ramps don't spring into existence fully formed: an artist thinks 'I want X, Y, and Z colors in my image', so they add those colors to the palette and start drawing, then after they have experimented a bit, finding the colors that suit the picture best, they expand these ramps (and may choose to try to make them cross over). Beginning with a complete fixed palette mainly only happens when doing artistic exercises (eg. Ptoing's EGA portraits) or commercial work. Most pixel artists will tell you their palette expands and shrinks organically.
So for most of the colors in your palette, I must say "why is this there? what is it for?". If you don't know, I recommend you remove that color.
Syosa takes a fairly extreme approach in that all ramps are oriented around a base color. This is good for achieving a watercolor-ish effect, as syosa's work exemplifies. If you don't want a watercolor-ish effect, then you may want to take a different approach to ramp crossover. In most images that share colors between multiple ramps, ramping is more moderate and ad-hoc than syosa's approach. Cure's "Pixel art tutorial" on PixelJoint forums
explains the different things that pixel artists do in the process of arriving at the final palette, including ramping.
Overall, the whole palette ramping and ramp-crossing can be compared to James Gurney's idea of
Gamut Masks. There is a tool
here that helps explore the idea.
