There is nothing in the Hermetic Code about affecting angels, but I understand that RoP:D explicitly forbids Hermetic Magic from controlling angels.
I see the possibility that a Tytalus might take up the challenge - either make a breakthrough to create angel affecting magics, or develop some other method.
Would Enchanting Music have a chance.
Could a Guardian Angel be talked into providing proactive teaching rather than just situational instruction?
I am being influenced by "Damiano" by ra McAvoy, where the title character is taught (music) by an angel.
The angel is willing to teach you the academic abilities it knows. It will not teach anyone else. ... If it ever thinks you are acting impiously or deliberately against God’s will, it will vanish, prematurely ending the
length of the fourth ring. It can also cancel any of the effects of the other rings of the Notory Art, and will do so to guide you back to the path of righteousness.
So it will treat a balky pupil just like the 'common donkey'-rabbi ...
"Controlling" is a bit vague. Hermetic Magic cannot affect the "senses" of Angels (because they apprehend with their entire beings, RoP:D p.20), nor it cannot summon or compel angels (RoP:D p.21) or cause them to act contrary to their Personality Traits (ibidem, this would seem included in "compelling", but...). However, barring a miracle Angels can be deceived, they can be manipulated e.g. via blackmail, and they certainly can be destroyed. It's just very difficult, and likely to invite Divine and Infernal intervention
Note that, while a miracle might prevent one from doing so, Hermetic Magic can already affect angels. In general, it seems to me that Hermetic magic already pushes the limits of what Magical abilities (i.e. abilities stemming from the Magic Realm) can do in regard to angels.
So,
Probably, not, at least not if it's Enchanting Music aligned to Magic or Faerie.
That said, a magus learning Holy Powers - in particular Adjuration - and combining them with either Holy Magic (i.e. Hermetic magic "aligned" with the Divine) or Holy Methods can definitely do more than via Hermetic Magic alone; so can a magus who learns Merkavah.
Sure, why not? It's a major Virtue, after all, and considering that mundane instruction can be had rather cheaply, I would allow it as long as the instruction provided is no better than that available from a good, completely mundane teacher (so e.g. no instruction in Supernatural Abilities, or at least in Supernatural Abilities stemming from Major Virtues, no Teaching Source Quality above 15-20, etc.).
Actually, there are two versions of this.
The Minor Virtue Faerie Instructor allows a Faerie to strike a bargain with a human, and either take an Ability of that human or give an Ability already taken from someone else. These abilities cannot be improved - they are exchanged "black-box".
The Free Virtue Faerie Trainer allows a faerie to actually have one or more human Abilities, rather than Pretenses, which can be improved (and taught) as a human would.
Don't have my books with me right now, but I believe infernal summoning and command can effect angels. You might be able to add Rego and Vim to these totals, but I'm not sure if it requires the hermetic sorcery virtue or not.
