Does watching pornography fall under "then indeed you are like them," and is the ruling on its perpetrator the same as that on an adulterer, and will he be resurrected with adulterers?

The verse implies similarity in disobedience, not absolute similarity. A person who watches pornographic films is not literally an adulterer, even though they share in the sin. They are considered metaphorically an adulterer through their eyes and ears, due to the Prophet's (peace be upon him) saying: "The adultery of the eyes is looking, and the adultery of the ears is listening."