In contrast to the rarity of the gift and of true faith, faerie powers can be learned by any character who has sympathy traits that total at least five.
So it seems to me that with some effort the Volkvy could
Step 1 get some of their people faerie touched enough to develop sympathy traits, then
Step 2 have the these folks develop their sympathy traits to a score of 3 (25 xp)
Step 3 use practical sympathetic influence to raise these traits two steps (to a total of five)
Step 4 teach them ceremony
Step 5 profit
In other words through hard work, faerie traditions can make their own apprentices rather than needing to find folks with the gift.
Also, given strong motivation and a few years to work the volkvs can gather significant numbers of ceremony participants to push their casting totals through the roof.
It is isn't faeries doing the planning, It's humans with faerie methods and powers.
The trick is getting a person involved enough with a faerie in order to get him or her a sympathy trait but also get him or her removed from the faerie's influence quickly enough that they are still usable.
Faeries live to enmesh Humans in stories, so getting folks enmeshed would be little challenge. Getting the humans freed would be where the problems may occur.