You don't have it. The spirit has it, and only casts it when the AI determines that the player in question needs Cure V. You have no control over the spirit casting Cure V, so therefor you do not have Cure V.
While possible to proc yellow (not called grellow btw), the spirit randomly casts the magic, not you. You have no control over the spell cast with the sole exception of which element it can cast. Because you do not have control over the spell cast, you do not own the spell and can determine if the spell is that right proc.
Pets are not players, and have no control over what they do (in the case of spirits). If they cast a spell to buff themselves, and in the sole case of Light Spirit, the player(s), they do not get aggro because they determined that the target needs the buff and casts the buff on that target, and SE also determined that, because the control of casting the spell is in the pet's hands and not the player's hands, the aggro issue should not come into play because the aggro will happen towards the player, not the pet, and be detrimental towards the player, not the pet. You do get aggro, however, if you summon a pet in the middle of magic aggro.
Exchange rates don't exist? If you want to cast Cure V, level WHM. If you want to proc yellow, level BLM/BLU/BRD. If you don't want to get magic aggro by casting, level NIN. You are assuming that this is like WoW and you can not change your job whenever you wish to, which you can (abet limitations of course).
Mala negative post count: 1000. Mala positive post count: 2 You have a 500:1 ratio of negativeositive posts now, congratulations!