In December I wrote to Mr. Windsor John, AFC’s Executive Director of Competitions Division, asking for details regarding the seeding criteria for the preliminary draw and group stage draw of the 2018 FIFA World Cup qualifiers (Asian Zone).
Got no reply, so in January I gave it another shot. Lo and behold, I got a reply from AFC - that's the second reply in 7 years. Mr. Man Gil Shin, AFC National Team Competitions Director provided the following bit of information:
"Please be informed that the latest FIFA Ranking available at the time of draw will be applied to the Draw not AFC MA ranking.
Thank you for taking note."
This means the January ranking will be used for the preliminary draw (if the dates announced by the UAE FA are correct), while for the group stage draw the April FIFA ranking will be used.
I will update this post to include simulations after the Iraq - Japan match is over.