I've been following this deck like everyone else and I too was skeptical considering the licensing. Sure there's decks that exist that bare similarities or are inspired by other intellectual properties. The Grid is an example of how a product can receive skepticism due to its similarity to existing properties. This is ok to do as long as you dont feature someone elses designs/product. The Core deck on kickstarter is also a good example. Its inspired by Iron Man and has his core reactor. However, he doesnt feature Iron Man nor the actual core reactor, the creator designed his own core reactor. In copyrighting a product, you can only copyright the design and execution of the product, NOT the idea. You can make a chair with your own design and take on the chair but you cant get sued by the creator of the chair just because it has a backing, seating and four legs. Those are the ideas which bring it together, but not the design and execution. Now it's tough when you have a product and say you have no affiliations to an IP then actually feature the IP as your product. There's no way you're going to avoid the proper legal leg work. I work in the motion picture industry and have had my fair share of dealing with IPs. It's no easy matter.
However, from the looks of things, this project was removed, not cancelled. When someone cancels a project on kickstarter the page can not be deleted. It just remains there but says the funding was cancelled. This project however, simply vanished with no trace. It appears it was taken down directly by kickstarter. If this was a legal issue, My assumption is Lego's legal team contacted kickstarter directly for a cease and desist. Kickstarter has to approve your project before it goes live, so they obviously saw the property and took their word for it and went live. Then here comes Lego, "blocking" the project. See what I did there lol sorry I couldn't help it.
I'm anxious to hear what the creators have to say about the ordeal.