AWB and Auto ISO in fast moving scenes I have recently asked about Auto ISO for video, and got great responses. I would like to have further clarifications in these regards.

I am planning to film an event in a public place. The scene will be fairly dynamic, and I won't have much of a control over what will be going on. I believe I won't have much time for settings either.  

For these reasons, I was planning to use AWB and Auto ISO. Specifically, I was thinking about setting the ND filter and aperture such that the correct exposure would correspond to ISO 200. That way, the camera should be able to go up and down when needed.  

Now, considering that each clip will be no more than 4 seconds, will I run into any issues with the above strategy?  

PS: I will be using a 5DMIII (no Magic Lantern).
It's a toss up either way.  On the one hand AWB may help you get better footage without needing manual correction later, but on the down side, if you end up needing any correction, it will change uncontrolled on you and will complicate the process of color correction in post.  If you don't plan to color correct in post and don't have time to adjust white balance on the fly, then AWB is really your only choice.

Auto ISO has similar problems.  It should generally do a decent job, particularly if you set good edge boundaries for the ISO (which the 5d3 does nicely), but it will shift on you and make adjusting for brightness and contrast in post more difficult.

Ultimately the shot you get is better than the shot you don't though, so if you can't operate it manually fast enough to get the shots, then use Auto for what it is there for, getting the shot you wouldn't otherwise be able to get.