Alright, I've worked through the charting. This is SUUUUPER simple charting. I've looked at whether or not Ifedi has one leg back, as a pass set, or both feet underneath him. Like these two examples. 
This is what I found. When Ifedi sets up in a pass set with one leg behind him, or with his feet kind of aligned, but still a bit behind, the Seahawks pass the football over 90% of the time. On the other hand, when Ifedi's feet are aligned, they run the football over 75%.
100% of Seattle's play action attempts came when Ifedi had his feet aligned, which makes sense, since that is when he is faking a run. On 66% of their play action attempts, Ifedi had one hand in the dirt.
I only charted Ifedi, but I noticed several times during the charting that I could also often tell whether they would run or pass by looking at what Duane Brown was doing. I'm sure you could study them even closer in detail and be even more successful in predicting run/pass
For whatever reason, the Seahawks clearly don't care whether they tip off the defense in terms of whether or not they are running or passing the football.
So basically, what I am saying is, that you have a mid-ish 80's percent chance of guessing run or pass for the Seahawks by ONLY watching Ifedi's feet. That's not even taking into account what the 4 other guys on the OL are doing.
Also, and this is not something I charted, just a feeling I got. But I think I would often be able to tell when Ifedi is the backside down blocker on a zone run, when he has aligned feet, and looks down the line pre-snap. Noticed that several times.
