The separation of the Hulk and Banner varies in Marvel comics. Sometimes, external forces or internal conflicts cause them to split, but it's not a consistent occurrence throughout all comics.
Red Hulk in the comics is General Ross after undergoing some kind of transformation. He's got immense power and is a force to be reckoned with. His appearance and abilities differ from the classic Hulk in several ways.
No. Marvel Comics is a family - friendly entertainment medium for the most part and does not include such inappropriate content related to sexual stories about its characters like Hulk.
It depends on the situation. Naruto has his powerful ninjutsu like the Rasengan and Sage Mode which give him a lot of combat power. But Red Hulk has incredible strength and durability thanks to his gamma - irradiated body. In a long - range battle, Naruto might have the upper hand with his jutsus. But in a close - quarters, brute - force fight, Red Hulk would likely win.