Really spending a fate point before is all about those dramatic situations when you really want to lay down the wrath on somebody.

I'm still not sure the arguement against Refinements applies.

There's nothing prohibiting a Focused Practicioner from knowing a tremendous amount about every field of magic.  True, they can only USE one, but they could know the theory about all of them.  (Note that Bob doesn't cast a single spell, and yet seems to be a vast repository of magickal theory and knowledge.)

   Second, mundane maneuver aspects, even if they are sticky, can be removed by anyone willing to take an action to do it. Most Evocation Maneuvers can only be ended early by someone who can dispell them (anyone can try to lift the bookcase you dropped on somebody, but only a wizard can get rid of the wind you used to pin someone down).
   For the most part I think it evens out.

Also, my PCs are commonly going around all together to interview people.

In the case of dealing with a reticent, intimidating but socially inclined opponent (such as, say, a Sphinx), should their "targets" be rolling their Social attacks against all the players at once (for example, rolling an Intimidation check against everyone at the beginning and dealing Social stress if the players fail their Defense rolls) or does any attack against a group need to be split like a Spray attack in a gunfight?

Just thought of this: should the opponent instead be using the Intimidation check as a social maneuver to set an environmental aspect Intimidating which can then be tagged for free in an appropriate later social exchange with whichever player it likes?

I'm having a hard time running Social Conflicts. It may simply be that the players haven't prioritized Social skills, but whenever I have an NPC who needs to be won over with social graces, the game just bogs down: the players roll poorly, and end up having to squander Fate Points. Any good threads, resources, or words of advice?

On the other hand, Intimidation is one way to apply mental stress that everyone can use. It has so many possible defences because it is so dangerous.

Lets say a wizard is casting a power 5 evocation with a conviction of 4.  He takes 2 mental stress.
Now lets say that he fails his discipline roll and chooses to take 2 points of backlash.

Does that mean that he takes one 4 stress hit or two 2 stress hits?