Per Cloud: is there a singular reason why he tends to isolate himself or is it just his default reaction to how he handles anything?

Per Julian: it's generally Heart because the Audacity is the source of feeling like you have the right to do/say/etc. such things. It can 100% be expressed in words, but unless his audacity is only in the sense of saying things (as in, he says things specifically to be inflammatory and not because he feels them), I'd say it fits more in Heart.