It seems that I'm stuck on a RNG loop with Ink Blue, Kobold Brown and Deepwood Green.
When I have Ink Blue, i feed my chocobo with a Pineapple.
When I have Kobold Brown, i feed my chocobo with a Plum.
When I have Deepwood Green, i feed my chocobo with a Valfruit.

Soot Black doesn't want to pop out .
I'll try to keep track the number of loops I do to see if how many loops I have to do before RNG decides to give me my Chocoblack.