Oh damn, hmmm. I think Wonder Woman’s character going from her stand-alone to BvS and JL would be very popular with Galadriel and survivors from the Third Age. Actually WW would be a popular movie for Beleriand, that leaving paradise with optimism about defeating evil only to face the fact that the real world isn’t black and white but to have faith in goodness and try anyways and that she does defeat Morgoth Ares. That would be cathartic. Man of Steel, with its central message of an orphan boy sent to be fostered in a new place for his safety, the outsider looking for his people, trying to defend the home he knows, who is inexperienced because of youth…like damn, I want to show Túrin that movie and promise him there’s a happy ending. Tuor too. I think Tuor and Idril would make in-jokes comparing themselves to Lois and Clark. Then the self-sacrifice in BvS, he would understand that and to show him the funeral scenes and Bruce’s speech. I think Finrod would love them all, and Beren and Lúthien. And the Valar. Maybe Thorin and the other dwarves too.
Suicide Squad is a funny one, because the premise is people thought of as irredeemable by society are being manipulated as tools but those in power, and yet the squad is able to find fellowship in each other and do the right thing in spite of the world. If the Tolkien characters can look pass the punk rock sensibilities, modern craziness, and the gray morality of the protagonist characters, I think they could like it. I remember Túrin redeeming the outlaws, so I think there’s a chance. Maybe Beleg loves it?
I have that idea about Batman in general starting among the Balar refugees – widely popular at the start of the Second Age.
Green Lantern: the Animated Series is beautiful space adventures of Space Dad and Space Uncle babysitting their AI daughter and helping Angry Space Zuko work through his beautiful redemption arc and then the later two have this star-crossed lovers and not sure why but I can see some Third Age people (Elrond) loving it. Elrond and his brother are huge DC Shills.
Thingol loves and hates Under the Red Hood because of how Bruce doesn’t reconcile with his son and Jason doesn’t come home.
Aquaman is going to be widely popular. Ironically not just the Teleri- there are some Noldor princes, not naming names, that get a kick out of Arthur stopping Orm and gaining the kingship.
The central conceit of DC is Godly Powerful beings trying to be human, and the movies that reflect that (BvS especially in my opinion) would be very popular with the Ainur. Gandalf understands their hope.