When Nikki met the Doctor, she was seventeen. She was investigating the criminal underworld of New Memphis with her father, who was also a private detective. After Nikki stopped the corruption of the underworld, a Judoon called Rok Ma joined her detective agency. (PROSE: Judgement of the Judoon)
Multi-adventures reference the rare instance when a companion is shown or stated to have multiple adventures with the Doctor but only appears in a single story.
If a medium is not mentioned, then this incarnation did not have companions who were original to that medium; it does not mean that this Doctor failed to appear in that medium.
