The scope of this wiki includes all content related to Psychonauts, its content, development, and community.
Pages can be made for actors, but should be made brief, and include only the most basic biographical information, along with their connection to Psychonauts. Consult this example from Nukapedia: Matthew Perry
A new article can be created for every item, ability, level, location, creature, and named character. Where there is a very small amount of content (one line) for a large series of related topics, it may be better to make one central list/table instead. However, you should not be scared to make a new page.
Articles are not appropriate for fan websites, people not directly related to the development of the game, or unrelated games.