That all sounds pretty exciting, but where would Alucard be in all this? We all know that with a battle this gigantic, he would have to be involved. Hell, it's the final battle against Dracula. And, I assume the idea to seal the castle inside the darkness of the eclipse was his idea. While, Alcuard could have gone back to sleep after the events of SotN, we don't know that he did. He could have been traveling the world and researching a way to put an end to Dracula for good.
I think that's what he did too. Alucard would very much be a part of it. My guess is that he has somehow made the threat known and has reached out to various other "mystical" organizations of the world. That he's the one who hears of the Hakuba priests, and, becoming an ally to the Japanese government as the mysterious Genya Arikado, enlists them to help combat the evil. Meanwhile, I'm guessing a Belnades(who becomes mother or father of Yoko, perhaps meeting and falling in love with one of the Japanese agents sent with Arikado and Hakuba) is allied with the church, and is also sent to heart of the fray. My idea is it IS going to be a World War type scenario, and various countries sending troops are also sending some of their holy warriors too to aid Julius, Alucard/Arikado and the others. Of course, not all prove their mettle(some might even fall under the influence of Dracula and turn against Julius and co.).