I´m not sure if I understood the concept of creativity as cause for faerie advancement (the rules are in RoP:F, p. 65). I´ll put my view in an example and would be happy if you´d correct me.
Imagine a highly cognizant faerie with a faerie might of 20 that acts as a wise woman and is interested in advancing her healing capabilities by gaining a supernatural virtue, maybe the Folkwitch Supernatural Major Virtue "Healing". The process needs the roll of a creative human and there is a pretense cost for the faerie, too. The first thing the faerie does, is collecting pretense points. The faerie has to search for a folkwitch and look into her pots (= observe the folkwitch while the folkwitch gains experience in her folkwitch healing ability). The faerie gets the same amount of experience points, but doesn´t spend them, rather she collects them until she has 35 of them (15 + Might: Gain a Major Virtue and a Major Flaw). Now she has to aquire the virtue by "changing her glamour", right? To do this, she needs the help of a creative human. His creativity can make the Virtue available for her.
My most pressing question is: What is a "symbolically related object or performance" (RoP:F, p. 65) - brought into being by an act of creativity - to "Healing"? The faerie may visit a sculptor that sculpts human bodies. Perhaps a painter is sufficient. But what, if there is only a minstrel with some sad lovesongs around?
Afterwards the faerie returns to the folkwitch, goes on with playing Nosey Parker and starts with the normal process of increasing pretenses.
Is this correct? Did I understand the rules? Is there a simpler way for the faerie to get the virtue?
Interesting! The birth of a human child is a an act of a "creative human"? In this case, what does "creativity" mean? I understood it as an attribute of an artist (or someone similar)... but maybe it is rather a quality of a creator - in the primary sense of "Creo".
Well, maybe not that simple. The character is an NPC, but I want to use the process of advancement as a story opportunity. The PC´s shall get the opportunity to witness the advancement efforts of the faerie. It should be possible for them to help or interfere. Does this idea fit into the rules?
Actually, by the rules as written the faerie does not need the pretense points to be related to the Virtue it's gaining.
So, it could gain those points by interacting e.g. with martial grogs hunting foul creatures, or with a lovestruck apprentice trying to charm the daughter of a minor noble.
Right, though she can also fuel the transformation with vis, rather than simply with pretense points: each pawn gives her a "discount" of 1 pretense point, up to a maximum discount equal to her Might.
Oh, the minstrel could compose a lovesong about how love cures all. The faerie would then be able to use the Healer abilty by using e.g. a small pouch in which she stores the essence of love, and uses it as a Sovereign Cure to heal people. Maybe she can require that those who are healed have someone loving them (or that they love someone, for whose sake they need to be healed). The lover must then allow a little piece of that love to be trapped in the pouch so the faerie can use it.
But note that the pouch is just an affectation, a prop that the Faerie creates because it facilitates her role: mechanically, she can use Healing as she likes, without pouch or love, but she pretends she needs love so that she can gain vitality from it. If someone has no love to give, she might instead give him some great quest, or take his pain instead. She could theoretically just do it for free, but in practice, which faerie would do that?
An alternative would be for the faerie to abandon her role, and gain a new one. A highly cognizant faerie can simply arrange her demise, and reform after a few months with a new set of Virtues, Flaws and Pretenses. See RoP:F, p.48. The total must stay the same, but they can be assigned differently - i.e. the faerie in question could swap three Minor Virtues or one Major Virtue for the Healer Virtue).
It's useful to keep in mind that initially "narrowly cognizant" was named "cognizant within role". So, your narrowly cognizant faerie can go after a new Virtue if a) that Virtue fits the role and b) its acquisition fits the role, because such a faerie understands the acquisition of power, pretenses etc. but only within the framework of its role. So, for example, a "captive faerie princess" could acquire the Healer Virtue to e.g. heal a hero who came to save her from the Bad Monster that keeps her captive. Gaining Healer makes sense for her as a captive faerie princess. But she probably would not understand how to gain Affinity with Artes Liberales.