No doubt it is IHC would you go Flagrant?
 

Definitely looks like K initiating contact prior to the ball travelling 10 yards (and no R initiating any blocks). So at least an illegal block on K.

As for IHC on K4, I'm not sure. Kinda looks like it from this angle. Flagrant? I don't think so.

I believe I've got flagrant IHC on this one.

It appears as if the football had broken the plane of the 50 when the contact was made. The fact that there is contact is not a foul. I agree this is IHC but it's hard to tell if it's flagrant, or not, from this video.

When I watched it the first several times, it didn't appear to be the case. And still watching it, I'm not sure. It is pretty darn close. Ball looks a yard short of the 50 to me. But then again, the camera angle makes it touch.

With regard to the kickoff? It looks like K initiates contact before R. So the question remains whether the ball made it to the 50.

Same here. Looks like he tries to deliver a blow with his arms, but his head is in the wrong position. From this angle it doesn't look like he intended to contact him with his helmet. But then again, the camera shot isn't that great.