Otto Stamper from Dredge's lore is not the same Otto Stamper from Doctor's lore
Basically, they're from two different terras/universes.
One is from base Haddie's terra while the other is from tome Haddie's terra.
Base Haddie in her lore finds the secluded island where the fold used to live as well as see the residual memories of when the people of the fold killed each other and created the Dredge, which by default means that Otto Stamper also lives in Base Haddie's universe as he was the leader of The Fold Community as seen in Dredge's bio lore.
Meanwhile we have Tome Haddie who is not only a different version of Haddie who lives in another terra, but she lives in the same universe as other characters such as Blight, Felix, Elodie, Twins, Vittorio, Knight, Carmina, Jonah, Doctor and of course, Otto Stamper.
Here is how that connects.
In one tome Haddie's tome entries called ''Twelve to Midnight. The Crows.'', there are references to some of the previously mentioned characters throughout in said story entry, those references are the following.
- A bottle of Grime: An obvious reference to Talbot Grimes aka The Blight, meaning Blight exist in the same universe as Tome Haddie and by extension Felix, Elodie and Twins as well. Felix and Elodie is connected to Blight because they and the other Pariah children finds the long abandoned East Indian Company laboratory and prison camp on Dyer Island that Talbot used in his bio lore, while The Twins are connected to Elodie because they are referenced in Elodie's bio lore.
- Painting of the Medieval lord: A painting of a Medieval lord who can see into other worlds which Max and Haddie finds along with The Crow paintings and other hidden things along with it such as different poetry, statues and art, a clear reference to Vittorio and by extension Knight since both directly know each other.
- The Crow paintings: The paintings that Carmina painted in her time before being taken by the fog that Luis in the tome entry kept with him hidden away which the mercenaries in the story is after, the paintings along with Carmina herself being mentioned by name more than once as well as herself as a killer appearing to max when he enters the bleed after he and Haddie finds the hidden paintings, meaning both Carmina and by extension Jonah exist in that universe as Carmina is referenced in Jonah's lore.
So now that we've established that Jonah exist in Tome Haddie's terra, let's take a look at Jonah's own tome, there we will find in the last entry this little reference to Otto Stamper and Herman Carter aka The Doctor.
Basically confirming that Otto & The Doctor both exist in the same terra as Jonah and by extension the same terra as Tome Haddie does as well as every other connected name previously mentioned.
So unless The Black Vale has found a yet to be confirmed way to travel back and forth between different terra worlds, it simply would not be possible for the Otto Stamper in Dredge's lore to be the exact same Otto Stamper from Doctor's lore.