Worth mentioning that Chocobos will use all the abilities they know in Free Stance, and stop using any weaponskills (or even autoattacking!) in Healer Stance.

Since we're very limited in terms of SP earned as the Chocobo ranks up it's looking better to go for a Hybrid Chocobo build and leave it in Free Stance constantly (unless you specifically need it to stop using any weaponskills or autoattacking and just heal you - in which case use Healer Stance!). When levelling up alt classes, I've found that you can usually get a Hybrid Chocobo to use its +enmity ability first if you put it into Defender Stance for the very start of the fight, but after that it generally holds better aggro and survives a lot longer if you put it back into Free Stance and leave it there for the rest of the encounter.