I agree. Though I also think the 4th is Naruto's father. I can't see him taking another person's son and condemning them to that kind of fate. as for arnel, there are clips for download on Naruto Chuushin and Naruto Chaos .
I've read up to 276 in the manga and his parents still haven't been revealed, so don't hope that it's going to happen any time soon...