It’s noticeable that the only companions mentioned in Night of the Doctor are from the Big Finish audios – Charley (Charlotte Pollard), C’rizz, Lucie (Miller), Tamsin (Drew) and Molly (O’Sullivan) – no mention of Mary Shelley, let alone Samson and Gemma. Now, in the Big Finish short Mary’s Story, several other companions are mentioned by the Doctor, including Gemma, Charley, Ssard (from comics), Compassion (from the EDA books), Trix (likewise), Destrii (from comics), and Alex (Susan’s grandson from Big Finish), plus the otherwise unknown Todd and Rita. So clearly, they are in the same continuity as Mary Shelley. (Fitz Kreiner, who possibly appeared in more books than any other Doctor Who companion, is omitted from the list in Mary’s Story, but he has his own story on that BF release, as do Izzy from comics and Bernice Summerfield who should need no introduction, so they can probably be counted in this continuity too.)
There is of course no guarantee that Mary’s Story is in the same continuity as The Night of the Doctor. In fact, one has to consider her omission a fairly big hint, especially considering that the Eighth Doctor at the end of Mary’s Story is heading off to the Time War, so would be unlikely to have forgotten her as he drank his last draught. If Mary’s Story hasn’t happened to the Eighth Doctor in The Night of the Doctor, then the continuities are unbound (spot the obscure Brian Aldiss reference there?) and we may have two (or even more) different Eighth Doctors in parallel timelines, one hurtling toward Karn, another to the Maison Chapuis beside Lake Geneva. I speculate that the central problem of Day of the Doctor is going to be how to reconcile the different timelines, or indeed to abolish all of them except the “right” one.
Oh gawd: “Will it Hurt?”
Edited to add: Futher to my Brian Aldiss comment, I had forgotten who played the protagonist in the film version…
Also, if you haven’t seen it yet, this trailer for An Adventure in Space and Time looks very promising: