Army Corps of Hell will be a 4-player Monster Hunter style game in hellish environments. Square Enix arent developing the title, however. Development duties are being taken on by a company named Enter Sphere.
Btw. Neither of S-E's Vita games are internally developed. There's no confirmation on Lord of Apocalypse, but I see no reason why it's not developed by Access Games, since they developed Lord of Arcana. Hell's Corps is developed by Entersphere.
What are the chances of Vita Ultimate having cross platform play with PS3 UMvC3? I just thought of that and if it could be possible, there's a strong chance that I may have to change a preorder and get that shit urley.