Defeating the Whip's Memory validated your proof of Belmont blood and enabled you to use the VK whip at full power. I don't know if it was ever said if defeating also removed the whole 'draining lifeforce' aspect, as didn't John Morris do the same thing with Eric and it still killed him? Of course, there's no such thing as being a "full-blood" Belmont, either. Having the Belmont surname didn't make you any more of a worthy fighter than not having it, so long as you were of the same generation as the last that wielded the whip at full power, or earlier. (Johnathan and John had just as much Belmont blood in them as Julius' supposed grandfather and great-grandfather, I would think)
Anyway...to answer some questions:
- Maxing out the Pie subweapon actually helps you with the fight against the Whip's Memory, so at least that's in your best interest. Maxing the Javelin out to get the Alucard/Alcarde Spear helps too, as it's as powerful or more than the VK whip IMO.
- OoE I think lands in around the time of Richter's kids or grandkids, so perhaps before CV64? (would explain how Drac comes back as a kid)
- The Bram Stoker's tie-in was done decently, IMO...but it could have been explained better in the fact that the novel could have been referenced a bit more. (ie: what happened with Drac's encounters with the Harkers?)