This colorblind pallet proposal would probably allow you to create very unique art, with an interesting style.
I am fairly new to pixel art myself, so take this advice with a huge salt rock.
Hue Saturation, and hue shifting when shading from dark to light was one of the lessons I was taught. Simply shading from a color to black will not always allow the intention of your art come through.
It might not be as helpful to show you this example if you can't see the colors, but let me try. Here is one that used the exact color palate from my online class.
The middle color is Green, but not pure green, just slightly off. On the lighter side of things, the color is a high value, low saturated yellow green, and on the dark side of pallet the color is a Green-blue. The tone of the green changes to the lighter side of the color wheel when looking at green things in sunlight. In darker lighting the blue-er value of Green, is more shown.
Since you might not be able to clearly see from the example, I'll list the HSV/RGB of each color.
Pallet values:
Base (green)
H:131 S:70 V:90% (R:69 G:230 B:98)
Green +1 light
H:122 S:67 V:92% (R:77 G:235 B:82)
Green +2 light
H:106 S:63 V:93% (R:123 G:237 B:88)
Green +3 light (notice the slight pallet mistake here... lol)
H:108 S:42 V:97% (R:163 G:247 B:143)
Green +4 light
H:93 S:28 V:100% (R:216 G:255 B:184)
Green +5 light
H:77 S:17 V:100% (R:243 G:255 B:212)
Green +6 brightest
H:64 S:6 V:100% (R:254 G:255 B:240)
Notice how the "H" hue value is slowly decreased until it's almost pure yellow.
Base (green)
H:131 S:70 V:90% (R:69 G:230 B:98)
Green -1 light
H:136 S:62 V:70% (R:68 G:179 B:97)
Green -2 light
H:145 S:67 V:54% (R:45 G:138 B:83)
Green -3 light
H:155 S:64 V:35% (R:32 G:89 B:64)
Green -4 light
H:168 S:58 V:28% (R:30 G:71 B:63)
Green -5 light
H:178 S:53 V:20% (R:24 G:51 B:50)
Green -6 Darkest
H:196 S:37 V:16% (R:26 G:37 B:41)
You can clearly see in the RGB that the darkest color has more blue then green!
The Hue shift seems to require a larger shift in secondary colors then in primary colors. However even primary colors in bright light, in pixel art take on the secondary color next to it, with a far lower hue saturation.
So in the case of Red, the lighter version of it might take a slight orange value, while the darker tone might take on a little purple/violet.
So I'm guessing there might be someone that knows a nice mathematical formula to evenly convert any color from dark to light, or light to dark, changing the hue in a subtle but natural way when shading that might be very helpful for you.
EDIT: Hue shifting, and how strong of a shift that is to be used can vary with certain subjects. Nature pallets use strong hue shifts, while inorganic pallets might not shift much at all. There is also style and personal taste to take into consideration when hue shifting, so just keep in mind that depending on the style you are aiming for, hue shifting might not be as critical for the success of your art.
What you have so far looks great btw.
G_G