Like Serio and DragonSlayr81 said, this is probably out of date now.
Why can it not just be an adaptation of Castlevania? That seems fairly logical: for a film named after a video game to be based on that video game. Sure, it doesn't have much of a story, but they could easily build stuff around "1691 - DRACULA RISES - SIMON BELMONT GOES INTO CASTLEVANIA - SIMON BELMONT DEFEATS DRACULA". Easily.
If Sylvain White has played the original Castlevania, then perhaps there is hope.
As has been suggested, you could then have Castlevania II (based on CV2) and III (based on CV3). They could add in bits from other games into those for storyline purposes. Maybe also a DXC movie based on Rondo and Symphony.