Some have disagreed with me on this in the past but I stick by the fact that Barlowe knew exactly what he was doing (as does Castlevania Wiki), and Ecclesia was a front to actually resurrect Dracula. The same idea was later used in LOS.
Well,
I have proven the Castlevania Wiki wrong in the past. I'll not discuss this point, but there is a whole lot of unfiltered opinion on the articles and I'd say you'd fare better not taking everything is written there as evidence (unless a source is provided, of course).
Shaft's body died in RoB/DXC and entered Richter's body at it's most vulnerable after his (and Maria's) fight with Dracula - refer to Iga's timeline. Dracula in SOTN's resurrection was made complete by his remains (relics) being gathered by Alucard imo. (The final room can't be entered without them.)
I disagree with three things here.
1. Dracula X Chronicles shows precisely the moment where Shaft got control over Richter's body. And it's WAY before Richter got to fight Dracula. It's before even he got to battle Shaft himself. Jump to 5:40 and watch from there:EDIT: This shadow is not Shaft - it is Death. The shadow keeps appearing until you defeat Death. Redoing the stage after Death is defeated causes the shadow to not appear anymore.
https://youtu.be/mp6gNFnPXuA2.
Given the above point, I believe Richter never got to face the real Shaft at all. The point above can be evidence for the fact that Richter was battling nothing more than a simple illusion, being already under the effects of Shaft's influence even before he got to the room where Shaft was. EDIT: The above point has been debunked.
At the end of SotN, Shaft's body can be seen inside the giant orb at the end, while an illusion of him talks to Alucard outside the orb. That scene is pretty damn good evidence he's able to create at least one astral-projection clone of himself that looks pretty much like him. This could mean that Richter might not have fought the real Shaft at all, but only an illusion of him.
3. I disagree in part with how Dracula got revived in SotN. While I think the remains had something to do with this, I also think Shaft sacrificed himself to revive Dracula. I say this because his plan was to sacrifice Alucard's human side:


This comes from the SotN retranslation from the japanese script. And if it's not enough:

This comes from the PSP SotN port. Here Shaft says that Alucard's soul is as frail as Richter's, and he even implies
Richter was the one to be sacrificed for Dracula's return.
He was not a host body as Dracula's throne room was still beyond "The gates of Hell" meaning he didn't materialise with any sort of host body.
I sort of agree more or less with this. I don't believe Barlowe worked as Dracula's vessel, too. But do you mean that you think Shanoa battled Dracula in spirit form? Because, if so, I don't think this is the case since what was inside the vessel was his remains:
Albus: They used [Dracula], Shanoa. [Dominus] is made from his remains. That's
HIS power. Nothing less.
Granted, there are also mentions of Dracula's soul being trapped in there:
Shanoa: ...Seal? You told me that was the vessel of Dracula's soul!
As per the DXC intro, you need both a sacrifice AND Dracula's body/remains to bring him back. So, while his soul is mentioned to be sealed there, his bodily remains also are. This could mean he has indeed revived with a body of himself. But if your point was simply about Barlowe working as a vessel, then disregard this point.