So thinking about anima magic, I've seen plenty of discussion re the mechanics but not a lot re the code. The magus has no control over the faeries he creates, whether they are transformed, summoned, or created from nothing, though he may be able to have a friendly relationship depending on the magus and the type of faerie. In response to that, it's a relatively simple matter to invent a ReVi spell to control them; but isn't that a blatant code violation? Especially if the faerie is summoned, rather than created, so goes back to the Faerie Realm when the duration is over, angry that you controlled it?
I see this as quite limiting to the utility of Anima magic, if you don't control it, you're left with social skills to charm and persuade or bargain with it; or the other good use I see is as a way to defend against hostile spells by transforming the spells into Vim faeries that wander off, or that you can be warded against.
The other thing I wonder about is the specificity of spell design - I get that you can't design the precise faerie you want, but are you limited to the broad definition in the guideline, or can you define a more specific role or type?
It's arguable as to whether it's a blatant code violation, but you would be pushing your luck. Does their vengeance catch your sodales?
Bargaining with faeries is covered by Faerie Lore (RoP:F pg 14), which Merinita will usually have good scores in.
The books are inconsistent on how specific you can be with your anima. Despite the HoH:MC rules being pretty restrictive, there are NPCs which have spells that summon faeries with clearly defined characteristics; see Patronus on pg 121 of Tales of Power, for example.
I'd probably rule that you can call forth a particular type of "existing" faerie, but the character can't just design a faerie that exactly meets their needs. So find an existing bit of folklore and say you want to summon a brownie, rather than saying you want to create a faerie with Power X and Virtue Y.
I have to wonder if one could use craft ability to design a faerie glamour before causing it to manifest with anima magic... hard to argue that it is closed to the artist before it exists...
Arguably the faerie in question is your magical property.
Given that the requisite virtue is a mystical secret of House Merinita there probably aren't any definitive quaesitor rulings regarding its usage.
In any case, other magi might have a difficult time discerning how (or if) a fae creature is being magically compelled.
Edit: Actually, IIRC, Anima Magic is taught by the Shadowmasters who count some Tytalus magi among its members...