Gokai Galeon Key which is going to appear in the Ten Gokaiger movie will transform Gokai Red into his Gokai Red Cross Armor Mode. The form doesn't have anything to refer to it as 'Cross'. So I guess similar to Kamen Rider Xross Saber, the word "Cross" might relate to the word "Ten" (十). Seems far-fetched a bit. But that's just my theory.
Three of the Gokaiger members are seen in black outfits. Joe Gibken (Gokai Blue) is seen holding a black pistol. The other three are also getting new outfits for the movie.
The new trailer which came out this morning has some interesting highlights
Fallen & Torn Gokaiger flag. They have disbanded?
Gokaigers fighting Past Super Sentai & Gokai Silver
Captain Marvelous (Gokai Red) says to Gai Ikari (Gokai Silver) - "Everything changed. You and also the people of this planet".
Marvelous holding his hand on the left side of his face near the eyes. He might lose his eye during the fight and he will be seen wearing eye patch in other scenes fighting the Sentais.