On the first video, stop on the frame when the ball is struck. If you are calling the player who is closest to the middle of the field as offside, that player in my opinion never becomes part of the play. As far as the player who ends up heading it in, I agree it is difficult to tell one way or the other but you have to admit it is close - maybe a body width at best.
I admit I am a homer on this - but as they say, sour grapes make the best whine. Good luck to all the remaining SW teams and I hope someone emerges to give Columbus and then St. Iggy all they can handle.