The video doesn't showcase Julius mode unfortunately. I have to wonder if they gave him a "proper"-looking Vampirekiller whip then the original version.
The only DoS hack I've played so far is the Juste Belmont one. The difficulty is a little up there, but I've managed to beat the game. Sonia mode I thought was a nice touch for an otherwise overlooked underrated character. Her design works well as does her backstory for the hack. The only thing I didn't get was why she has such a short VK whip. It should be the same length as Juste's since it 'IS' the same weapon. A bit of an injustice for her I feel. Not only that but it should be the fire whip since Juste also has access to it in-game. At the very least it looks like we see it in SotN/PoR.