Bases loaded 0 outs son hit a hard ground ball, takes a big hop, grazes runner going from 1st to 2nd. That runner is out, Does the run score?

I thought the ball is dead right then, batter takes first and thats it.

I have a question along the same line:

If the infield is up and the ball hits the runner behind the fielders is it dead or alive?

No, the run does not score. The ball is dead and runners return to TOP base. Batter/runner goes to first.

When the infield is up and the fielder has a chance to make a play on the ball, but the ball goes past the fielder and the ball hits the runner, you have nothing.

CB is exactly right. The ball is dead and all other runners return to their bases. As far as the fielders playing in, there is a slight difference between Fed and other codes. As CB said if it passes close enough for a fielder to have a play, then it live. This true for everything except FED. They still use an older concept called the string theory. If the fielder is closer to the plate than the runner, whether he has a play or not, then the ball is live.