1. "Run it by him" = bring it up and explain it to him and see what he thinks.
2. "Throw sb a bone." = We can't give this person all of what he wants, but let's give him something, even if it's only part.
3. This one is crude. It means that if a trip to Las Vegas hadn't occurred, the person would have married any woman just for the sex.
4. Yes. a stay-at-home son is someone who lives with his parents.
5. I have been intending to ask someone, but haven't done it yet.