Hmm... not so sure about that.
Remember, unless an event outright states that something happened a certain way, it cannot be assumed that it happened a different way.
So, since the Bloodlines manual (and Iga?) state that Quincy Morris is a Belmont and helped deliver the final blow, we have to take that as canon.
Since nothing else says otherwise, it cannot be assumed that there was too much of a difference between the Dracula novel and the Bloodlines events. IGA and others have tried to wrangle and entwine these two storylines, so we have to accept that some events are either similar enough to be the same event, or linked close enough that they can work together, and create your own headcanon by filling in the blanks.
The mere presence of the whip is already too much of a deviation from the original story, and you can draw some conclusions from that. If Quincy used a whip, then there must've been a Lecarde to unlock it. Therefore, the whip is probably the cause of Quincy's death. This is already a BIG deviation from the Bram Stoker account.
IGA said that Quincy was lifted from Bram Stoker's Dracula, but this doesn't necessarily mean that "sans the differences" the whole thing is the same. If we try to fit that story in the canon, too many conflicts arise for it to be feasible without a major overhaul, I believe.
And now there is the thing that young Eric and young John witnessed these events unfold. I'm almost 100% that his bit doesn't exist in the japanese manual, so here we go again:
Character bios from the japanese version:
http://www.vgmuseum.com/mrp/cvbl/packaging/vkill-manual9.jpghttp://www.vgmuseum.com/mrp/cvbl/packaging/vkill-manual10.jpgStory:
http://www.vgmuseum.com/mrp/cvbl/packaging/vkill-manual2.jpgThe story has been translated here:
http://www.vgmuseum.com/mrp/cvbl/documents/CVBJ.txtCan someone confirm if their presence there is mentioned?