Or no Hobbits at all...

[Galin]

Well, on the languages, Jackson chose much fabricated Neo-elvish over much of Tolkien's actual Elvish in the books.

But this provides yet another example of how little appreciation Jackson had for the tone and "feel" of Tolkien's work. Yes, Jackson went to considerable length to include Elvish in the movie: but he did so mostly by _discarding_ Tolkien's _own_ Elvish exemplars -- which, please note, are almost entirely in the form of songs, poems, spells, and exclamations made in crisis or _de profundis_ that are used sparingly so as to punctuate the story and to not cheapen the effect of the Elvish -- and instead substituting for them long passages of made-up "Elvish" (however skillfully) constituting (mostly banal) _dialogue_ of the sort entirely _missing_ from Tolkien's own application of Elvish in his story (or anywhere else). As such, it is really part-and-parcel with Jackson's treatment of all of the source material: it touches on it, it _appears_ (at first glance, and on the surface) to be almost reverential towards that material, and yet on further consideration in fact mostly and quite badly fails to capture, present, or even to understand the most important themes, aspects, and tone of the work, substituting instead Jackson's own really quite shallow, banal, and clichéd sensibilities.' Carl Hostetter

Disagree with this if you like, but to my mind Jackson didn't have to go to the Estate or anyone to represent Tolkien's Elvish, just the books basically (maybe to someone on pronunciation, though the books are quite handy there too).

In any case, what proof is there (I'm not saying there isn't any) of Jackson wanting to go to Christopher Tolkien, or anyone who is actually part of the Estate, for advice on languages, costumes, architecture, for a more accurate vision of Middle-earth? And how far was this going to go, even if true? And did it include advice on story too? proper emphasis on battles or monsters? important themes? advice on characters?

The section quoted in the linked interview is quite brief: who exactly was 'dealing' with the Estate and about what?