As far as Konami picking up Seal of the Eclipse, crazier things have happened, and successful games like Sonic Mania started from the fan community and ended as an officially published game, but that isn't common.
I have some experience pitching to Konami. A few years ago, Konami Europe started an indie publishing program, which ended up publishing games like Skelettack. This publishing program is for games more like Seal of the Eclipse and Carpathian Night, which are smaller games made by truly indie individuals or studios. I pitched Carpathian Night to them, and they reviewed it, but they felt it wouldn't be a good fit because the messaging would be confusing - a Konami game that looks and plays like Castlevania, but isn't Castlevania? And since this is a completely separate program from anything related to their main IPs, its not really in their power to just turn CN into an official Castlevania game. We did end up getting rejected.
I think Konami would only be willing to talk to established studios with a proven track record for anything Castlevania related, but they also have avenues open for smaller guys like us with original indie games, but we just weren't a good fit.