mickeyfan2 said:
In Narnia they are all adults now. They are only kids in "our" world. So it might not be as problematic.
If the new title is true then they are skipping "The Boy and His Horse."
I always assumed the children started off each time in Narnia in their current earth age. Prince Caspian, for instance, takes place over 1000 Narnian years after Lion, Witch and Wardrobe, so clearly they are not going to assume their "Narnian age". They are supposed to enter Narnia about a year later earth time, so they should be about a year older for the events of Prince Caspian.
The other books they are all in are The Horse and His Boy (not the other way around

) and The Last Battle (except Susan). Of course they are adults in Narnia during Horse and His Boy, so that's easy. The Last Battle does not take place for another 8 years or so (earth time) after Prince Caspian, so that also is not pressing yet. Edmund and Lucy are in Voyage of the Dawn Treader, which takes place one earth year and 3 Narnian years after Prince Caspian. The toughest thing might be Eustace, who in less than a year, ends up in Narnia twice, in Voyage of Dawn Treader and Silver Chair.
Given those facts, if they were going to do all 7 books (which seems unlikely), they would probably do them in this order:
Lion Witch and Wardrobe
Prince Caspian
Voyage of the Dawn Treader
Silver Chair
Horse and His Boy
Magician's Nephew
The Last Battle
I guess the last 3 on my list could be juggled somewhat, but I would think they would want to end with The Last Battle, as doing another one after that would seem odd.
Regarding the suggested reading order, that has been debated, so whether or not they "skipped" Horse and His Boy is debatable.
I know next to nothing about film-making, but I have always wondered, couldn't they film some of the scenes they will need later now, while the children are closer to their correct age? I guess that could get complicated in the case of Narnia, as they overlap with other characters, such as Eustace , who overlaps with Jill.