Syntactically puzzled

Elizabeth asks a question over on the Purdue Linguistics Association blog:

I saw this in a Christmas letter I got:

This year will be our hopefully last Christmas in #Exico.

#(place-name changed to protect the innocent)

So, what I want to know is, what is going on with "hopefully" in this sentence? Traditionally it's an adverb, but here it's hopped over into the noun phrase. The sentence sounds grammatical to me if I imagine somebody inserting the "hopefully" at the last minute as if they didn't think of it in time. But then how did an adverb get in that position? There are other adverbs that don't sound like they could do that:

It looks to me like it's still functioning as an adverb on last -- and it sounds fine to me in any adverbial position.

will hopefully be our last Christmas in X.

will be hopefully our last Christmas in X.

will be our hopefully last Christmas in X.

*will be our last hopefully Christmas in X. -- (unless said parenthetically)

So it can't modify an noun as we see also in another sentence type that Elizabeth suggests:

This box will hopefully be the one I need.

This box hopefully will be the one I need.

Hopefully this box will be the one I need. (that old bane of the prescriptivist)

?This box will be hopefully the one I need.

*This box will be the hopefully one I need.

?This box will be the one hopefully I need. (It might only be okay here if it's changed scope to revert again to the prescriptivist's nemesis)

This box will be the one I hopefully need.

Elizabeth importantly points out that surely won't work like hopefully:

This year will surely be our last Christmas in Exico.

?This year will be our surely last Christmas in Exico.

There's almost some hypallage going on here altho that's typically an adjective moving to another noun. In this case 'hopefully' as an adverb wouldn't be starting on any noun but I think it might be. Let's look at it as a special case of transferred epithet moving from "I am hopeful" to the special semantically widened scope that "hopefully" has taken starting off a CP. Because yes -- it's odd that hopefully seems to have some license that other adverbs don't. Perhaps it's because a word like "surely" hasn't earned the legs that "hopefully" has. But has importantly? How do you feel about my sentence above where I displaced important from its place modifying the point that Elizabeth makes and I put it on her method of making the point? Does it look to you like it's freer than 'surely' but not as free as 'hopefully'? That's how I hear it.