I can't comment on the other answers so here is my piece to the other answers:
The letters are the way it grades the Stand according to the stat. The translated text is what determined what the stat is.
The stat at the bottom is the Stands ability. Abilities are something like; Magician Red's fire, Hierophant Greens possession, and (spoiler alert!) Star Platinum's time stop. Hermit Purple's stat in that category is high because of its ability to reveal other stand users and make superhuman observations.
Attacking a Stand just hurts the user. Durability is never really brought up as something that a Stand can have since the durability is simply based on the user. I have no idea if there is a Stand with armor so basing a stat on that instead of ability just seems like a mistranslation to me.