So basically

So my first thought into this is : the common-most ghosts of the Nether-Realm .

The most common colour we ever see are Red, Green, and Blue . And there aren’t even a lot of yellow ghosts ( yes, I do know that for some reason the pointy-heads said they had all the yellow ones, but I will get to that, I promise ) Which the fact the ghosts were most commonly this scheme instead of either ‘green and orange’ or ‘red, blue, yellow’ it can’t be that specific, can it ?   So this is where I thought about what colours blend from what in each respective scale . So drew out this :

SO BASICALLY, my thought is : What if Pacolopis, having a lot of peeps primarily in the Orange and Lime scale was also the idea that it was the most common blend of genetics between peeps . And the only reason ‘Cyan’ and ‘Magenta’ are not seen as so rare is because while the shades of Cyan and Pink seem to vary more, Yellow ends up looking more Orange / Green depending on how much of what genetic you get .

  I will also try to estimate Spheros and Betrayus’s Family Tree with this  Roundtunda is Orange, fairly Common ( As we’ve seen ) .  Spheros is Lime, ( fairly common ) .  Betrayus is White and Black ( I believe both are a part of this and I will get into it in a bit ) .  Elliptica, the nephew, is a lilac-pinkish/purple . Now lets look into the likeliness of each colour : - Spheros being Lime would be very much possible if Rountunda’s Partner ranged from ( Counterclockwise ) Orange ( Being Less Likely, but Still Possible ) - Opposite Blue ( Which is the end line for possibility of any colour between them ) - Betrayus seems like it would be the most likely if Roundtunda’s partner was the Opposite Blue ( I think the perfect balance of all three in equal doses would be the mixing scale or either black, graey, or white . ) - Elli, being a nephew, would likely fall under both her parents being in the ( clockwise ) Red - ( Orange’s Opposite ) Blue If say, Rountunda’s Partner was Opposite Blue, it’d be the most likely to not only explain Betrayus ( and Fred ) as a slim, but very possible thing . That could also give the idea that if Betrayus and Spheros had a secret sibling, that sibling would likely be in the blueish range because the opposites can blend in both directions .  And said blueish-sibling having a partner of the specific range that could have Elli be plausible could give an explanation for the full family tree coming together . ( And said silbing could even be between a later partner, after dating / divorce / whichever Roundtunda ) I was also thinking, perhaps that while Yellow Ones maybe more uncommon in Pacopolis, maybe in another part of the world, maybe the specific Cyan or Magenta colours may be important ?