Is seeing kissing or anything arousing without explicit intercourse, or seeing others having intercourse in a dream, considered a wet dream? And is the semen that is released due to a wet dream the same in color and smell as that which is released during masturbation? And what is the reason for frequent wet dreams?

Ghusl (definition) (ritual bath) is only necessitated by the emission of semen. There is no difference between semen emitted through a wet dream or masturbation, except for the sin involved in masturbation. Semen has distinct characteristics such as gushing forth, pleasure upon emission, and the subsiding of desire thereafter. Its smell, color, and consistency may vary.