“I would have made this instrumental, but the words got in the way...” —XTC, “No Language in Our Lungs”
“Self-discipline isn’t everything; look at Pol Pot.” —Helen Fielding, _Bridget Jones: The Edge of Reason_
Maybe start with this suggestion from their contact page?
Permission to Use Requests
Hasbro receives a large number of requests for use of Hasbro’s intellectual property and trademarks. If you wish to submit a Permission to Use Request, please fill out this form and return via email to firstname.lastname@example.org. Permission to Use Requests typically take 1-2 weeks to process, however some requests can take up to 4 weeks. If you do not hear from a Hasbro representative within 4 weeks of submission, we unfortunately are unable to approve your request. While we do review each submission, due to the volume of requests, we are simply unable to respond to every inquiry. Permission to Use is not granted without express consent from Hasbro.
I know you're looking for a license and not just permission to use IP or trademarks, but this might be a good place to start. The 4-week waiting period also seems worth knowing about.