I wonder how much the heat will affect things. At least it will be under 90 and dark by that point. Given how much Flanagan focused on her heat problems after the marathon trials last year, and doing well with it in Rio, I wonder if that will help equalize things and offset her relative lack of training. Presumably no one is going to want to push the pace too early, but then that will benefit the better kickers (Conley, Infeld). Flanagan might have to take off with 2-3 miles to go, late enough to not blow up but early enough to do some damage.
Huddle obviously a lock no matter what the scenario is.
I'm wondering, since Cragg is committed to doing the marathon at WCs, if she'll serve as Flanagan's personal rabbit. I could see a scenario where Amy and Shalane break from the pack early, with Cragg grinding out the pace as long as she can, hoping to drag Flanagan to a big lead.
They seemed to form a strong bond while training for the marathon trials, so I don't see this idea as being that surprising.