Following up on the large layout for 8th Edition rumors, I did try and get some additional information regarding Admech and Sisters. Here is the response.
I will also update this on the main article. Fingers still crossed for a combined Ad Mech in 8th Edition and a new Sisters of Battle Full codex release.
via anonymous sources on Faeit 212
The Imperium in Campaign 3 (Nids vs Orks vs Imperium Vs Necrons) is heavily Ad Mech and Astra Militarum and less Space Marines (most of them are in the EoT in Campaign 2) so maybe that would be where combined Ad Mech comes in (or maybe even before then to pave the way for the campaign?) Adeptus Sororitas I admit I havent heard anything about where they fit in all this.
Previously on Faeit 212
40k 8th Edition Campaigns: An Exciting Look Ahead