What would that do as opposed to a border of 1? Would it let you cross without magic? I wouldn't think so... but there's no such thing as a 0 shift spell I don't think, so I don't see what mechanical difference a 0 border would make vs. a 1 border.

It might be interpreted to allow crossing into the Nn as a 'minor effect'.

Enchanted Items can't actually give you '+X to action Y' effects (again, despite what the printed examples might suggest).  What they can do is replace the roll entirely with the strength of the enchantment.
(ex. you could have a strength:10 potion which allows you to take an Athletics sprint action as if you had rolls a total of 10, and fluff that potion as temporarily transforming the imbiber into the wind itself; good for getting to relative safety when ambushed by a nasty toad-demon)

Temporarily boosting your powers is also permitted within the rules by way of the Temporary Powers mechanics.

An invoke-for-effect of an appropriate aspect might be able to temporarily suppress the ability of another aspect to be invoked or compelled.  That's the most direct RAW mechanism by which I could see a spell completely suppressing a Consequence for whatever duration.  I'd talk it over with the group, though, because while it's not quite as powerful as actually healing the consequence (the slot is still occupied, and the spell will probably wear off before the consequence heals on its own unless there's a Recovery power involved) it is still quite powerful, and a savvy player could easily get quite a lot of 'bang for their buck' if it's allowed to apply to larger Consequences with no additional cost.
On the less reaching side of things, simply having a spell that applies an aspect (or, for a ritual or enchanted item, possibly more than one aspect) related to exceptional health, vitality, life force, etc, and then using the resulting tag(s) and subsequent conventional invokes to counteract any invokes (basically just going point-for-point) and argue (/negotiate) the narrative (in)appropriateness of Compels related to a Consequence.

You can't seem to see the math because frankly, it's not there.  The example spells, items, and often characters in the books frequently go beyond (or around, or through) what would otherwise be inconvenient rules preventing them from achieving the effect they desire.
The result is that you get evocation spells applying aspects to a zone (or even everyone in a zone) or initiating grapples, potions giving armour vs casting stress, and other things that the rules simply don't allow.

Does he want to cure himself of the demon?  Or does he want to cure himself of the hunger?
The idea of 'ripping the demon to pieces' gave me the idea that he could 'consume' the demon, taking its powers for himself directly, without its influence, but in doing so inheriting some of its weaknesses (the need to feed on that particular emotion, etc).

Mechanically, this would be almost identical to a standard WCV, with only an Aspect or two necessarily being differentiated.  Thematically, however, the difference is significant.

Those things already exist in the Nevernever.  Somewhere.

The only strictly RAW option would be to have a Block in place before the attack.

It also might be possible to have a stunt allowing Discipline to be used as a defense skill with some restriction.
IF such a stunt were possible, it might be possible to spend a FP for temporary access.

By RAW FPs are awarded based on Consequences taken, not merely those remaining at the time of the Concession/Take-out.

Houserule as you will.


edit: On a side note, I'm back!

Conventional Enchanted Items can be used beyond the uses paid for via enchanted item slots, specializations, and foci by spending a point of mental stress.