You do a good job of adding a lot of extraneous information that really doesn’t apply to the issue at hand. It’s pretty simple: no matter where the money is, if it’s a student asset, report it as such (student-owned 529 accounts excepted).
We’ve been around the block with this before. Here’s a thread from just this past January where you and I and others discussed this very issue:
The FAFSA rules regarding jointly owned assets are clear enough. Whether or not the individual completing the form wants to follow the rules remains a personal decision.