The difficulty if you don't "lawyer up" is that then you are a non-lawyer talking to lawyers - because the people on Disney's side who you would talk to would be lawyers. That is not in your favor.
If you need to talk about the law, then you want a lawyer.
You need a professional to make sure you get everything that you're entitled to and someone who knows how to negotiate so she gets the most appropriate terms.
For example, if she does this on her own, she might be well compensated but also unknowingly give up her copyrights in te deal. A good lawyer will be her advocate and make sure she understands everything she is about sign.
If you need to talk about the law, then you want a lawyer.