Hi guys! Long-time lurker first-time poster =D. Anyways I don't think I saw an actual real summary of what's been said about that Doujin so I'm going to try to sum it all up.
The person who is dead is indeed Genya (Subaru and Ginga's Father). In the picture of the funeral the people I did not see are Shamal and Teana. From right to left it goes Signum, Vita, Hayate, Nanoha, Vivio (she looks like she doesn't really understand what is going on lol.), Subaru/Ginga, and Fate holding the umbrella.
I could be wrong but as far as I can see these are the people there
. Shamal and Teana could be dead too because I don't think I've seen Teana or Shamal in any of the pictures.
Anyways. Going by the summary Hayate becomes the leader of the TSAB after leading a coup d'etat. She does this because the TSAB was doing nothing. She then turns to Jail to make a cyborg army to combat the mass-based weapons that killed Genya and are also killing many people in the universe. Under her leadership the TSAB forsake the ideal of "an organization that did not depend on weapons other than magic to uphold the peace." Of course there were some who did not agree with this.
That would be Fate, Shari, Caro, Erio, and whoever else is with them. I'm not sure who else is but yeah. They stick by their ideals and oppose what Hayate is doing. They are rejected and branded as rebels and they run to the ends of the universe where they meet the enemy which is the cyborg army, and their former comrades.
I think that the Betrayers in the title is Hayate, Nanoha, Signum, Vita and the cyborg army because they betrayed their ideals and started using weapons other than magic to keep the peace.
Fate and co. are the minority and the ones branded as rebels. Nanoha and co. are the majority and are still part of the TSAB and they are the ones known as Betrayers.
Heh that was long =]. But this is what I got from the summary and from the pictures. I want to see the epic battle between Nanoha and Fate D=. Can't wait~~~.