the hopkins one is tough to tell, as we don't have a perfect angle to see it. the main broadcast angle sucks because one of the coaches head is directly in the way of seeing his foot. this one shows he might have stepped out, but again, it's impossible to know how much of his foot was on the ground. you can make out some white chalk flying up, but not sure that's conclusive. either way, the refs made the call on the field and wasn't reviewable. honestly, in these 50/50 plays, i do believe the refs SHOULD let them play out and have the chance of reviewing it, rather than calling it dead
as for the late game runs, i think miller clearly had it on 3rd down and they gave a bad spot. o'brien definitely should have challenged it and would have won imo. for that one, it doesn't really make sense to look at a still picture, because you could easily have a pic with his knee down and the ball past the marker, but with a still shot, you dont know if he fell forward after the knee was down, or if that snapshot is actually EXACTLY the moment the knee went down. but if you look at the video, i think its pretty clear miller had it.
the 4th down play is harder to call, and while that spot was questionable, i'm not at all surprised they didn't overturn it. honestly, if the call on the field was a first down and the raiders challenged it, i dont think they would have overturned that either. it's hard to make out where the ball was positioned relative to his body at the moment his knee went down. sure, his head was past the marker, but the ball was tucked in