Per a brief post from LYT of Topless Robot at San Diego Comic-Con.
QuoteLegendary just confirmed that Godzilla's sequels will have Mothra, Rodan and Ghidorah. Legendary also announced a new King Kong film called Skull Island.
I sincerely hope the Skull Island film will be backstory to Jackson's film, as that had a lot of interesting potential (explored in a tie-in novel that I never read). But anyway, they didn't say Kong would be part of the milieu -- after all, Legendary runs the Nolanverse and Pacific Rim and other properties, too.