As an Alliance the Emperor needs to have access to the guild leaders. So the guild leaders need to be in Emperor vent and guild vent simultaneously. The Emperor can then communicate with the guild leaders who will then communicate with the raid or guild. Not only does this keep the pvssyr down it also protects vital intel from spies. The emperor will need raid teams, sabotage teams, and small armies for reinforcement and taking less guarded keeps. The guild I'm in intends to be a sabotage team, a small, tight, and highly specialized team for those missions the emperor needs done fast and quiet. In the end we need not just emperors but generals. The emperor leads the generals and the generals lead a force composed of specialized guild alliances. ...Also as a raid we need buffers, not just heals and dps.
This is going to be a two front battle and those are tough to win. I really doubt anyone will be able to push both sides simultaneously to both scrolls, but what you can do is deceive the enemy. If the Ebonhearts push into Aldemeri's border with Daggerfall and take those keeps they can change the face of the battle. If the Ebons hold the keep against the Aldmeri but abandon it to the daggerfall then it will cause a skirmish between the Daggerfall and the Almeri, from which the Ebonheart heart can then push into the Daggerfall flank on the Ebonheart border. Effectively giving the Daggerfalls a two front war. At that point you push hard for those scrolls while fighting a single front war against an opponent fighting a two front war.
As the Ebonhearts If you have the numbers you can push both borders halfway into both alliances, then remove your forces from Almeri lands to reinforce the armies against the daggerfall alliance. You will be fighting a single front war against the daggerfall with better numbers while the Almeri will be preoccupied retaking their lands.
At any rate I think the strategy will be in keeping your alliance in a single front war instead of a two front war. Making it to a single front war is going to take great communication, immediate response and guilds that are team players. The alliance that cant get their guilds to work together is the alliance that will fail. You can also verbally ally with an alliance but I don't think that will happen unless the numbers get real bad.