Mindblanking Dalla changes nothing. This operation has too many people involved to fully protect it.
The important bit is that both Dalla and Doran give us multiple potential sites to choose from and that we don't commit before very close to the actual attack to minimize the timeframe in which we are vulnerable to divinations.
In other news, killing old Bobby B is something that has far reaching ramifications, so maybe it's time to nail it down.
In even more different news, I also want to nail down something that I'm very attached to, namely that we officially crown ourselves on the day before the invasion, so that we can officially declare it "pacifying the unruly western provinces" instead of gracing Tywin and the other suicidal lords with calling the whole operation a war. This will be barely above pest control.
[X] More Diplomacy! More Invasion! Also, some regicide!
-[X] Diplomacy
--[X] Have Roderick the Reader start the diplomatic efforts to organize a secret Kingsmoot in the Iron Isles in the middle of the 4th month. Justification would be Roderick seeing the need for a clear and strong leadership of the Iron Isles, since Westeros is visibly coming apart at the seams these days, and the secrecy being necessary to prevent foreign meddling.
--[X] Have your Riverlander collaborators try to nudge Hoster Tully to leave Riverrun with a small contingent of loyal knights to support Lysa Arryn, as raising the banners in the current situation will be all but impossible and might cause so much chaos that he can't help her at all, leaving Riverrun in the capable hands of Edmure Tully.
-[X] Invasion
--[X] Ask Dalla to scout for a well-hidden valley near the Bloody Gate that can be used as a staging ground for a Darkenbeast company.
--[X] Ask Doran Martell to look for a well-hidden valley in the Red Mountains that can be used as a staging ground for a Darkenbeast company to attack the Marcher Lords.
--[X] Send a team of engineers to assess the state of Harrenhall and to make plans on how it can be rapidly refurbished with Titan Tools to serve as a major base for the Legion and the Airforce.
-[X] Far reaching things:
--[X] Tell Bloodraven that Robert Baratheon has also outlived his usefulness. He can help Cersei kill him in a way that should be blatantly obvious to be the work of the Lannisters.
--[X] Announce your coronation for the 30th of the 4th month.