If I can't blend colors together to make a new one or use colored transparent pixels,  could I use dithering to simulate blending while still sticking to the palette? Also, for the Anti-chromatic diversifier, does that mean I can use any shade of the same hue or am I limited to 8 shades?

EDIT: I would also like to ask that if I decide to use the Anti-Chromatic diversifier, can I include a "Palette Swap" option for a multi-color palette?

Yes, dithering is a great solution as long as the individual pixels remain within the palette limitation.

Palette swap is pushing the limitation, but if it’s set at the title or a title menu and cannot be changed during game play it’s fine.