Just curious, do you have the permission to be selling products with copyrighted material (names)?
I won't say anything, but in this day and age people are sue happy for any reason.
I appreciate your concern. If you would like to discuss the amount and substantiality of the original appropriated (1), the transformative nature of the derivative work (fan art), whether the derivative work was done for educational or noncommercial use (yes), and the economic effect that the derivative work imposes on the copyright holder's ability to make and exploit their own derivative works (none); I would be willing to discuss privately.
American copyright law allows for the production, display and distribution of derivative works if they fall under a fair use exemption, 17 U.S.C. § 107.
Buyers should check their local laws before bidding.
