2Cor521,
I strongly recommend contacting the financial aid department of the relevant college(s) to answer these questions. Based on my, now decade old, experience with FAFSAs in graduate school, I agree with your answers to 1, and 4.
Initially, I agree with your respond eto item 2. However, you may need to report it elsewhere as additional resources for your son.
For item 3, why wouldn't you report this as child support paid? This seems like an incorrect reading of the item.
I wish you good luck with the form and I hope the educational experience goes well for your son,
Karl