Alice is performed in the audio book by Jenna Coleman, who normally plays companion Clara Oswald in the TV series. In the continuity of the TV series at the time of the audio book's release, it had been established that many echoes of Clara existed through the Doctor's life, assisting him. Whether Alice is one of these echoes is not indicated overtly in the story.
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.