Whether or not the distinction between "fan" and "professional" for products is meaningful depends upon your definitions. If the logic behind the category distinctions runs that a publisher such as Wizards has more resources to put into a product than a fan does, where does "more" become significant enough to matter?
When you get down to it, the resources WotC/Hasbro can bring to bear on a project are much greater than those possessed by most other publishers in this market. The difference is so great, in fact, that if we're talking about the spectrum of possible resources and relative places in that spectrum, WotC is at one end and most publishers would be grouped way over on the other end, close to, or in among, the "fans." How great is the difference? When I ran the Pendragon fiction line, our annual budget for printing all our novels barely matched what WotC spent on a single promotional campaign for one Drizzt novel. Yet one of those Pendragon novels would have to compete with the Drizzt book in the Regalia category.
Some awards use how much people are paid for creating the product as a dividing line. If someone working on the product gets a salary from the publisher or is paid x cents per word as a freelancer, it's a professional product. Anything below that line is an amateur or fan product. You might want to consider that.
If this is the place to make other suggestions, let me repeat my annual request for the awards to recognize the individuals who create the products being recognized. Publishers deserve recognition for their roles in bringing the products into existence. Without the individual staff members or freelancers doing the design or writing or editing or artwork, they have blank pages.
And you may want to rethink the name for the "regalia" category. "Regalia" might be a suitable name for a design or art award category, but it doesn't work as a portmanteau category designation for novels and other products.
Cheers,
Jim Lowder