Yeah, it was really easy for the person I picked, I found their personal website which I reach out to first but never heard back, then I reached out to them on twitter and also never heard back, my last ditch effort was to comment on a post, but also never heard back :/
Maybe the people who run the cart design contest or however those carts are made, they could do a check box to agree that the carts could be used in game jams and then we wouldn't have to hunt permission down.
But I'm still pretty happy with what I made so not a huge deal.