As usual with AFC, it's very hard to get information regarding their competitions. In 7 years, they have replied only once to my e-mails.
However, the United Arab Emirates FA have posted the draw dates on their website. Use Google Translate if your Arabic grasp is lacking.
Preliminary round draw: 10 February
Group stage draw: 11 April
The April date is also confirmed by an English article on the Japan FA website.
AFC have announced the schedule. The preliminary round games are scheduled for 12 and 17 March, while the first two group stage match days are set for 11 and 16 June.
The format is already known - a preliminary round to get to 40 teams, followed by the group stage - 8 groups of 5 teams each.
First all of all, AFC teams won't be involved in the main draw set for 25 July, because at that time they will have played 2 matches in the group stage. Can't quite imagine FIFA going for this, but you never know.
Now, you might ask how will AFC determine the teams involved in the preliminary round. Will they use the FIFA ranking? If they do, does the January ranking change things?
I will answer the second question first. No, it makes no difference.
Going by the FIFA ranking (December 2014 or January 2015), these would be the pots:
Pot 1: India, Sri Lanka, Yemen, Cambodia, Chinese Taipei, Timor-Leste
Pot 2: Nepal, Macau, Pakistan, Mongolia, Brunei Darussalam, Bhutan
However, one of my sources in Asia told me AFC won't use the FIFA ranking. They chose their recently released AFC MA ranking.
If this is correct, it will mean good news for India, Nepal and Pakistan.
India will avoid the preliminary round, while Nepal and Pakistan will be seeded.
It will be bad news for Bangladesh (now involved in the preliminary round), Cambodia and Chinese Taipei - losing seeded status.
Pot 1: Yemen, Sri Lanka, Bangladesh, Nepal, Pakistan, Timor-Leste
Pot 2: Macau, Cambodia, Chinese Taipei, Mongolia, Brunei Darussalam, Bhutan
Of course, some withdrawals are expected and Yemen, Sri Lanka and Bangladesh stand a good chance of going directly to the group stage.
I have no information regarding the seeding for the group stage draw.