I'd also see the power level of some items in the Councils hands would keep others away from pushing them over the edge. At least with Eb holding the Blackstaff everyone (who needs to) knows where it is, same most likely with a few other item's in vaults in Edinburgh.

Small pile of the books in a jumble sale - picked them up, liked the first, then read the rest.

On first reading this one does seem overpowered, for the following reasons

• that with Ill Communication the ability to or just robbing them of its use entirely will remove a lot of power from a lot of things, which for only Exhausted seems very powerful - though you would also have to deal with the powerful thing afterwards.
• that the Logomachy becomes very general in scope, rather than being specific.

I can also see use of these powers been seen a violations of the Laws easily - and possible even some of the more zealous Warders going for a pre-emptive strike.

Would possible go for the following:
Ill Communication: Mark Exhausted. For the rest of the scene you can use your linguomancy in strange and unusual ways. You may place an aspect on the scene that extend your gift to others, either allowing everyone to be understood regardless of the language they use or that no one can understand anyone else.
You can create a cipher intended for a specific person which only they can understand. The is a create an advantage action using Intellect; you get +2 to these rolls, a symoblic link with the recipient is required.
You may place an aspect that has a linguistical bases (giving them a nickname which becomes real, for example) on another character, they can oppose your action using Focus. At the GMs discretion your linguomancy gains the benefit of Supernatural Scale.

And on thinking about it Logomachy, works as it has the limits of Evocation on it, so does have some restraints, and as long as opposing or defending rolls are allowed should be fine.

Also see lots of potential to have things come back and deal with you from using these powers.

Also some location aspects might only be there for the short term such as:

• Pitch Dark
• Blasing Inferno

These aspects describe a feature of the location, and can be used by any one present

Some more permanent ones might be

• Really bad smell of decay
• Crumbling structure
• Quiet and out of the way

Again may be good or bad for everyone.

I'd guess that some of this could be covered using the "Spellcasting powers and stunts" rules from the The Paranet Papers (p275-6). This would give access to extra things beyond the normal - though would need to describe a new set of powers, such as advanced elemental affinity. Also could see a variation on the "Breath Weapon" power for throwing fireballs around.