As mentioned by others in the thread, I am very confident that (our) Lahabrea's true name will end up being Hephaestus.
Also I am presuming that the events of Pandaemonium are taking place after the MSQ Elpis events (I feel like that's the natural default assumption until stated otherwise), and since the MSQ referenced the "Ere Our Curtain Falls" Tales from the Shadows has having already happened, I am guessing Themis is already Elidibus at this point in time (plus him wearing white robes also indicates that since they said only Elidibus and living former-Convocation seat holders wear white robes), but is concealing the identity of his status.
At the very least the events of Pandaemonium have to take place after the "Through His Eyes" short story, since the story stated during the lead in to the Phoinix fight, that the Words of Lahabrea have finished the finalized concept of the Phoenix already.
I do wonder if Azem predicting the WoL's arrival to help Themis is meant to indicate that Venat decided to let Azem in as part of the select few individuals she would tell about her knowledge and plans of the future. Or if it's indicating and/or leading to something else.