Well...assuming all that's true, I suppose that's a reasonable ending.

Still, making the Venatori some kind of Nazi extermination squad and the Black Court anything but completely irredeemable monsters is the kind of thing you should really talk about with your players, since it's a setting change on par with there being no White Council or Laws of Magic...

It's not a lot to go on, but it is enough to include in some fashion, and there's enough context and other information that we can make some reasonable assumptions as to the details.  (also note that I did not suggest 'complete immunity to mental powers of all sorts'; what Bob conveys is actually more potent, if, strictly read, more narrow than my suggestion)
For instance, that particular resistance is mentioned seperately from the Loup Garou's general resistance to physical injury, so we can reasonable assume that it is, in fact, seperate; that it does not merely refer to spears of force putting holes through the creature's skull as a means of dealing with it, but rather refers to mental magic.
Moreover, Harry's interactions with the Alpha's shed some light on how we should likely inerpret the term 'sorcery' in this context.  Specifically, that would be 'incredibly broadly'.

These are assumptions, but I view them as relatively safe in the absence of further information to the contrary.

Like I said, I'm not saying you're wrong necessarily, just that it seems a stretch.

In all, there are likely certain rare 'mental powers' to which such creatures should be vulnerable, as well as certain applications of a wider range of powers that should skirt the edges of their resistance, but for the vast majority of cases, the classic mental whammy should fall wholly flat when pitted against the likes of a Loup Garou.

I'm sorry, but the most common mental power we have (Incite Emotion) is both radically different from most direct magical mind control and exactly the kind of thing that should potentially work on a Loup Garou thematically...so saying that only 'really rare' powers work on it seems profoundly wrong.

If that's the sole goal and sole contributor to the assessment of success, then 'coming back in the morning' isn't really even necessary.  Just take a few hours or days and drop a satellite on the general vicinity while they're in their human form.  Or hire some mortal thugs to pop off a few magazines into the guy while he's sitting on the john.

Assuming they have high Resources or Thaumaturgy and no fear of Lawbreaker, I guess. Just killing him personally is easier for 90%+ of characters, though.

I'm sure there's a nice celestial event sometime in the next month or two that would make one of those 'cosmic vending machine' rituals available that would suffice to do the job if we've already established that we're not on a schedule, and that there are no (relevant) consequences for delays.

Assuming you happen to have access to one, which is an even bigger assumption than having Thaumaturgy or a lot of money.

Or using mental powers. Or avoiding the combat. But at heart, I agree. It's an interesting hypothetical, but actually playing it out seems relatively pointless.

I prefer the simpler, less potentially broken, use of Discipline and Conviction maneuvers to stack up some navel-gazing Aspects. Works perfectly well both thematically and mechanically.

First of all: thou hast violated the Fifth Law!

Second: The bit you refer to is explicitly only about Focus Item Crafting. You can't have a Focus Item that makes crafting other Focus Items easier. Having one that boosts the Strength or Frequency of Enchanted Items is totally allowed. Re-read the page you cite if you don't believe me.

Corpse Body seems to be trumped by having any Recovery power...including Wizard's Constitution. Making its downside less than biting. Still, you may have a point, and actually being death-immune should be worth something. -1 is clearly around the right price if following that logic.

I actually am enjoying the fact that this is causing tension among your PC's. The players seem to be playing as their characters not as players who are running a character. Ultimately it MIGHT be in everyone's best interest to kill The Rukh but emotions are getting away from people.

It makes for interesting stories and better games.

I agree with this. I disagree with the GM's seeming reactions, though. those smack of the exact opposite - putting the fact that it's a game over the legitimate interests of the characters. Especially the prohibition on inter-PC conflict.