Kratos might win. He has fought and defeated many powerful gods in his own world. He is not only physically strong but also very strategic. He could analyze the Hulk's movements and find his weaknesses. The Hulk, while strong, is more of a brute force fighter. Kratos could use his Blades of Chaos to keep the Hulk at a distance and then strike when the opportunity arises. Also, Kratos has faced opponents much larger than him before and has always found a way to win.
Sure. Thor and Hercules have clashed multiple times in different comic series. Their fights often stem from differences in power, ideology, or the circumstances of the story.
Thor would have a good chance of winning. His powers are not only physical but also magical. He can summon lightning storms and has the ability to heal himself. Darth Vader, while a formidable opponent with his dark side powers and lightsaber skills, is still mortal. Thor could withstand a lot of damage and keep coming back at Vader. Also, Thor's hammer can only be lifted by those worthy, which gives him an added layer of protection. If Vader were to try and grab the hammer, he would not be able to, and Thor could use that moment to strike.