> Pink Diamond's powers allow to give sentience to plants
> Said plants are humanoid, with relatively consistant colors and no actual human organs
> Onion and Yellowtail are named after vegetables
> Both are yellow for the most part
> Onion han never been seen swallowing anything, and is stated to not like food
> None of them seem to age as a human would
> No one knows who Onion's mother is
> Sour Cream isn't actually related to Yellowtail

Shit dude, you might actually have cracked the code.