Some thoughts …
I like the idea of Monica using the Arcane as her in with Harry.
As to the rest …
I have little doubt that Pappa Raith was the one behind Victor and the spell. I think Pappa didn’t have to DO anything with Vic to get it going. All he had to do was to provide access to some books that had the spell in it. Remember it’s a Cha-ching spell. The White Council could easily have had it published to get it used to dilute it like they did lots of other books. It had simply fallen into dis-use.
As to the notion that it was a RC spell that hadn’t been used in thousands of years, I could see one Black Council member (RC King) talking to the Pappa Raith to get him to find someone to test the spell. Remember, magic changes over time. If it hadn’t been used in awhile, it may need tweaking to get it to work right.
To me Papa Raith would have gone for the kill with Harry, not try to get the ball rolling. I can see Papa teaching VS, but He would have started screaming "Kill him! Kill him! KILL HIM!!!" once Harry got involved because he believed that Harry had to die for him to feed again.
I think this would have gone WAY away from Pappa Raith’s nature. I think he’d still want to use a catspaw and not be so obvious. Besides, someone already pointed out that he didn’t know Harry was Maggie McCoy’s son. (I know she’s Maggie Dresden, just wanted to throw that out there.)
Serack – I know in Curses it’s stated that
Harry love, the Queens of Winter and Summer do not kill mortals and so frown on their followers taking such action, but the High folk of the Tylwyth Teg have no such restrictions
However it does not say that they CAN’T, just that they don’t and frown on their followers doing it. Self-imposed limitation, not necessarily a “law”.