A phone's number isn't its "true name" - you can change it (without changing the SIM or any hardware).  You can also keep the same number and get a new phone, so... yeah, it's just not a very firm connection.

Besides, how far can you stretch that?  If you know my email address (which is a gmail account) could you locate my computer?  If you know my birthday, could you locate my mother?

What human is really going to link it mentally more to their monthly statement than to themselves?

Um, me?  Hell, I can barely REMEMBER my own phone number.  After all, I never dial it.  That goes for pretty much all phone numbers- nobody memorizes them any more.  My wife's phone number?  Hell if I know.  It's "2", in my mind.  (Voice mail is 1)

Remember, all the props for working magic are simply shortcuts, according to Harry's testimony. All it really takes is a clear mental concept of what the target is and what you're intending to do, and the props are easy shortcuts to doing that.

If that's the case, why do you even need the phone number?  Seems like just thinking about the person you want to find would be equally valid.  But of the shortcut is needed- well, some shortcuts are useful, and some just go in circles.

LOL- fair enough, I forgot that the high concept is an aspect like the others (only more so).

To me this sounds like its an attempt to create the aspect "Blowing Up (In) My Hand" or some such.

So yeah, basically what's needed is a consequence (maybe more than one) you create on yourself and can tap offensively. 

Normally that would be a maneuver, but since the aspect is being taken as a serious consequence (grenades can blow through armor plate at close range, so a hand with even mythic toughness probably isn't much challenge, and just adds more shrapnel) I'd say there's no need to maneuver.

The "Total ecovery" benefit of recovery powers would not apply: "you cannot  recover  from consequences with time, because your body does not regenerate."

The "Faster Recovery" benefit could; basically you'd be a lot easier to "patch up" (using taxidermy, etc).  But you still wouldn't heal automatically; it would just cause the injury to be as easy to repair as a lesser injury.

"Unfaltering" et al could easily apply; it just means you have supernatural stamina, totally fitting for the undead.

I'm not sure on "It's Nothing" et al.  On the one hand, it's pretty much a form or healing.  On the other, it has limits on what it can do, so it could easily represent being tough enough to get (say) you guts blasted out, then just tucking them back in and ignoring it.

Yes, game-mechanics wise, there is very little to recommend fists over guns or weapons.  You can't accidentally kill somebody in DFRPG, fists flat out do less damage than weapons, and weapons can grant special aspects etc.

But story wise, using the Fists skill can make all sorts of sense.  First, its one of the few combat skills that "civilians" might train to high levels.  And as mentioned, bringing a weapon with you is often considered rude, or can get you in trouble with the cops.  Also, you don't always want a weapon in your hands during a fight; fists leaves your hands free for anything you like (such as grappling, taking the enemies weapon away, picking up the McGuffin, etc).

Even mechanics-wise, fists aren't so bad; you don't hit any less often, and only do a bit less stress with each hit.  If you have some maneuvers to tag, you can still stack up quite a hit.  And since you often have to draw on the first attack (-1 supplemental action) to use a weapon, which might cause you to miss, the gap is smaller than it looks.  As long as you have a strong defense and don't let maneuvers against you pile up, you can wear the enemy down; your fights just last a bit longer than they would if you used a weapon.  And story wise, that can be a good thing!

From the books there are a alot of instances where harry will not use magic to do things, because his control is not great enough.  As far as I see the rules really don't support this.  The discipline roll is only important when you are using more power that you can easily handle.

The novels may do this to further the plot; having Harry use magic to solve everything would be rather dull.  In game mechanics terms, that would be a compel on some aspect Harry has, earning Harry a fate point.  This might be a self compel (say of "Not so Subtle, Quick to Anger"), reflecting the fact that Harry over-estimates the trouble he would have contolling his power, or actually has an abnormally hard time controlling it.
Actually, it seems like a pretty good idea to give a low-refresh character an aspect they can self-compel this way- something that lets them earn fate points for complicating the plot by NOT using their powers, whatever the reason.  Good for the story, can help make some extra screen time for the mortals when things would otherwise go the supernatural route, and a good way to stock up fate points.

Yes, I'm pretty sure you could buy all newly manufactured replacement parts for (say) a classic VW bug (something you can do even today) and build up a full "mage tolerant" car.  Its not the date of manufacture that matters, but the technology used.  Honestly, anything that doesn't have electronic fuel injection should probably be OK, though it might have other systems that get messed with (say, they used a solid state switch for the fuel pump).
I don't think you'd see a commercial car built that way, but a custom car easily could be.  Heck, a lot of race cars actually are mechanical throwbacks with no "luxury" electronics in them.  If you want a commercial product, you could probably find a motorcycle that was "mage reistent", and could certainly get one made,

As to electronics, I don't think "hardening" would help; I see the effect as being quantum in nature, which means it can mess up anything that uses even simple semiconductors (eg, transistors, diodes).