@col-klink 

Even if this is what's she's doing, I still am very afraid it's too risky a decision for the venture. I did imagine that multiple voices speaking at the same time as one might be a direction she chooses to take to give the visual/audio suggestion of three in one without having to explain it in a more complicated fashion. I think something similar has been done in films with pagan deities. And of course, one voice could dominate or take a central role depending on the moment. If it was my choice, I'd want the scene in the garden and the apple to be a male's voice. But I'm also comfortable with a director exploring established theology in a creative way without freaking out. I think most Narnia fans would agree that if we weren't comfortable with that, we never would have been comfortable with Narnia in the first place. 

We'll see. I'm just not convinced that Meryl being cast means Greta is being disrespectful. I still think it could be a mistake. I hope they test the waters some more. Surely, nobody feels like losing more money in this economy. This feels like a career-ending mistake if it goes wrong. It just takes one ill-received, expensive film to do that. Plus, I'm not sure we'd get anything else Narnian for a very long time.

It doesn't matter what a voice actor is doing during the time they're shooting the film. Surely that actor comes in during post production only?

@coracle I'm really not sure, never having been involved in an animated movie (or a non-animated one, for that matter) — maybe somebody else here has some more direct knowledge. But I remember once, years ago, seeing a "making of" film about the BBC's beautiful (and ultra-faithful) series of adaptations of Beatrix Potter's stories, made in the early 1990s. One thing that stood out to me — and I hope I'm remembering it correctly, over 30 years later — was that they did the animation after the characters' voices were recorded, and carefully timed not only the animated characters' mouth movements, but also their physical gestures as they spoke, to fit exactly with the already-recorded voices, pretty much syllable by syllable.

That makes more sense to me than doing the animation first and then recording the voices, because in that case, the voice actors would be having to synchronise not only the timing of their words, but also their tone and expression, to fit in with an existing animated sequence. I can imagine that would be very difficult to get right and would make the voice actors feel really hampered. So I'm guessing it's standard to record the voices first and then create the animation. But I could be wrong, and I'd be glad to hear from anyone else who knows more for certain.

@coracle   That is another really good point, that a voice actor isn't really needed until pre-production, so it will be a while before the voices are finally decided on, once the technical bits are already organised, & it is time to see how the bits connect?  I can't pretend to know anywhere near as much as yourself about acting, let alone film production, when I understand you've had much experience with Narnia theatre productions. 

@cymru   So...I've had to ask myself what could they be thinking if this is the direction they go. Knowing Greta's influences and how she does deep homework for the thing she writes makes me wonder if:

1) Meryl won't be the ONLY voice of Aslan. 
2) Aslan's voice could be made of multiple voices.
3) Aslan's voice will change with each book/adventure in Narnia based on the story and adventure itself.

Though I agree that Meryl won't be the ONLY voice of Aslan, I'm not so sure of multiple voices, EXCEPT where even the book MN, itself, positively calls for it, such as in MN's creation scenes, when Aslan's own song mingles with those of a chorus of stars.  But I do agree that Aslan's voice might well change with each book/adventure as needed, especially when he appears in various forms.

I've been trying to think what Aslan does in each book:

1. In MN, it is our first introduction to him, really, even if MN was the last book to be completed.
2. In LWW, it is mainly moods we see, & his sacrifice, rather than shapeshifting.
3. In HHB, Shasta is comforted by the cat, and then there are the three voices (Myself) on the foggy mountainside. We also see Aslan not only scratching Aravis' back, but also a personal visit later on at the Hermit's place, as well as at Anvard, when dealing with Rabadash. 
4. In PC, his appearance is more ethereal, only gradually reappearing. A whisper in the wind, perhaps, when Lucy was trying to wake up the trees? But a deep roar, when the Pevensies & Trumpkin get to Aslan's Howe. What about the romp through Narnia? And the people he meets? I nearly forgot Reepicheep getting his tail restored, & the way Aslan organised the return of the Pevensies to the Railway station. 
5. In VDT, Aslan appears on Dragon Island, to un dragon Eustace, on Deathwater Island, growling. At Coriakin's Island, where they meet the dufflepuds, but mainly to Lucy, during after she reads the book, where he claimes to have been also "unvisibled". At the Dark Island, Aslan was the albatross that said "courage dear heart", then met them at Aslan's Table, on Ramandu's Island, to restore the three remaining missing lords, Revilian, Argos and Mavramorn, the lord who wanted the mustard. When both Ramandu and Coriakin are supposed to be stars, would any reprise of the star music from MN be warranted, at sunrise, and when Ramandu gets his bit of coal delivered by a flock of birds? And then, there is the time he appears in a lion's head effigy on Caspian's shield, I think, as well as the Lamb who gives Eustace, Lucy and Edmund some breakfast at the End of the World. 
6. In SC there is Jill's first meeting with Aslan, on the mountain top, her dream of the rocking horse turning into Aslan in Harfang, and meeting Aslan at Caspian's funeral at the end. 
7. LB. This is where it is going to be tricky, when we have a false Aslan - a poor donkey dressed up as Aslan, and the real Aslan at the end. 

Have I forgotten anything?