ok,  this misses some of the key points and misstates it a bit. I appreciate your effort though.  Precise definition is difficult to paraphrase, isn't it?

"other authorities agree that they will not overrule"
their agreement is not necessary, only the legal right to not be overruled 

De facto sovereignty, the second, is actual power,  
'the actual exercise'  'actually using'...etc.    of that power.  But 'power' that's a word that can't be used in this sense without FURTHER definition,because it's too ambiguous outside of a context that specifically implies what meaning is meant.                                  

I think if we have the word 'exclusive' (the key point) in the opening paragraph, the rest can be saved for the later paragraph, where it is now... sparing people who just want the overview from reading mumbojumbo, but retaining the info for those who want a more thorough exposition.

If a sovereign state can make a decision but cannot carry it out, the recognized sovereignty of the state is essentially meaningless.

I think this is a splendid summation of the concept of defacto sovereignty  I think if we 
keep the defacto vs dejure info in the 'differing views' section, it ties together the 3 seemingly different views by the common thread of, "no matter what your view is on sovereignty , you have to have it to use it and use it to have it"

and if we add your summary it makes the 'differing views' section just about right. 

A key element of sovereignty in the legalistic sense is that of exclusivity of jurisdiction. 

Specifically, when a decision is made by a sovereign entity, it cannot generally be ovverruled by a higher authority.  Further, it is generally held that another legal element of sovereignty requires not only the legal right to exercise power, but the actual exercise of such power.  ("no de jure sovereignty without de facto sovereignty") In other words, neither claiming/being proclaimed Sovereign, nor merely exercising the power of a Sovereign is sufficient, sovereignty requires both elements. 

If a sovereign state can make a decision but cannot carry it out, the recognized sovereignty of the state is essentially meaningless.

But if I may? I think this is one tiny bit better, as it applies to the anarchists, monarchs,etc:
If a sovereign - person or state - can make a decision but cannot carry it out, their recognized sovereignty is essentially meaningless.

In that form, I really like it.  How does that read to you? I think at this point the article is accurate, and pretty safe to expand on.  If the readability issue is good, (I'm blind to that, Ive read too much legalese to notice much if it sounds stilted or awkward), I'd say we are pretty set. Want to pick at it a bit and post your change?  I think it's a consensus at this point, pretty much.