Hi Erkz.
Your Boss Rush Hack was greatly good. Congratulations to you Erkz. I would suggest a few things, like the ability to put that Boss Rush mode as a 'game mode' usually to be selected along with the Arcade, Versus, Training and Network modes as standard. Here's a picture assembled by Photoshop to show how it should look:

Another thing that could be better is to find a way to enable G-Akiha and Dust of Osiris bosses as playable characters. See this photo montage here:

But not only them, but also the Boss Rush versions of Warachia, Arima Miyako, White Len, Aozaki Aoko, Koha & Mech, Dust of Osiris, Ryougi Shiki, Tohno Akiha and Archetype:Earth (PS2 version), all with their styles fighting in Eclipse Style always available for selection (except Akiha that uses a special version of Half-Moon Style) and choosing them by simply going to the corresponding character, holding the Shield button, that is the button "D" and selecting the character. The Eclipse Style will appeared at the time the Style Moon selection screen appear, indicate that the code would work.
Exactly like in Melty Blood Act Cadenza PC when needed to choose Neco-Arc Chaos to play with him.
And lastly, find a way to put the "Eclipse Style" for all characters in the game, allowing you to choose the Eclipse Style after selecting the character and if possible, put all the movelist of three other moon styles of characters (but without removing new ones that may be included ) and edit them a bit the "cpf" files to let the characters using this style of play a little bit even more difficult than normal.
Well, those are my suggestions. Be free to comment and tell me what you and his friends think of these ideas.