Re: Brauner, his grief awakening magical powers may have just turned him into a Vampire over time whilst dabbling in those powers rather than it being instantaneous. Though we know he is a vampire in the traditional sense as he can turn others.
I also wonder whether Brauner's transformation parallels Dracula's, they both lost a person(s) they loved and despise humanity because of this. This make me wonder if others can draw upon Chaos as a power source the way Dracula does.
I dunno if we think alike, but I believe that Sanctuary wouldn't work on Brauner or Dracula because they weren't turned. They became vampires through other methods, while Vincent and the Sisters were turned unwillingly.
Yeah basically anyone bitten by a vampire which is kind of like secondhand vamp smoke.
My hypothesis is basically this:
Brauner, as a painter, even if he's very creative (just look at the circus themed paintings), he would have to have seen something to inspire him before actually painting something.
I agree with your theory in part, the "power"of the art comes from the
inspiration itself coming from within the artist, not necessarily in the surface subject matter, I'll explain this below.
For instance: Even though the circus paintings are very surreal, one still needs a basis on a real circus to be able to paint that.
I think this is slightly out of context.
One only needs a grounding of how/what something is platonically to envision something which can be both real and conceptual like a 'circus'. It's a general thing, it's kind of like describing 'an aeroplane' or 'a house'. One may know common associations or elements which can stitch their own conceptualisation(s) together, but this doesn't mean they necessarily require extensive knowledge of that thing. (Brauner doesn't strike me as the sort of guy who spent his life going to the circus every week

)
The first circus painting is called "Nation of Fools", this is perhaps the best application of Brauner's inspiration into his art with the corresponding in game level. Let's take this as an example and I'll explain why.
List 1There are Typical Circus-associated elements you'd find such as:
-Rings of Fire
-Clowns
-Acrobats (being fired out of canons) onto tightropes
-The "circus tent" (background)
List 2There are also non-circus elements which are prevalent:
-Soldiers that stab you (violence)
-Clowns that attack you with playing cards (violence)
-Acrobats that throw knives at you (violence)
-The Legion (boss) consisting of numerous naked bodies of people revealing a central nucleus
-The environment (architecure/ landscape) which is twisted, contorted towards a central nucleus - as is the Legion
List 1 are the typical, generic and platonic elements associated with a circus
List 2 are the non typical associations which seem to liken the masses "fools", "clowns" and all things associated with Brauner's idea of the nation. Additional elements in List 2 which usually wouldn't be associated with a circus are, predominantly to do with violence or the attempt to kill the one experiencing this environment/ world/ reality as one does with art.
(In this case the player Jonathan/ Charlotte is experiencing the art.)
List 1 merely serves as a context and/or facade ('canvas' - albeit interactive - if I may) for which Brauner's thoughts and inspiration take physical form.
List 2 are the undertones, beliefs and underlying thoughts/ ideas/ inspiration of the artist which manifest taking physical form.
List 2 supersedes list 1, Brauner is bereft of compassion or empathy towards humans. He despises them and sees them as a 'nation of fools' where seemingly otherwise normal people have turned violent and started to slaughter one another as casualties of war. This is evident in the environment; its twisted state/ contortion mainly in physiognomy but also in enemy placement, the nucleus which reflects the consciousness of the masses (which the player has to slaughter to get to the core of) etc.
Even though List 2> List 1, context is still important. It would not make sense to have the Egypt stage as "Nation of Fools" because it wouldn't fit. Therefore List 1's theme/ motif still does complement List 2 and that is how both are configured.
Brauner's inspiration of how he views this nation in this example is what is taking precedent in these paintings.
It is too 1-dimensional to state that it's a painting about pyramids, or circuses or a forest so that's what he necessarily has to have seen.
I'm not taking aim at your ideas and rationalisation, I'm just stating there are deeper undertones to what is going in the context of these artworks, specifically relating to the artist's inspiration.
Even though the pyramid paintings have impossible concepts, he'd need to know what the pyramids are and the Egyptian themes surrounding them to actually be able to bend the concept with his creativity.
He was probably a very intelligent man, however I stand by the fact that the environments themselves at a surface level need not reflect how something platonic like a "pyramid" actually is inside.
Given these stages in the game it's likely Brauner did however have extensive knowledge of certain periods of history and civilisations.
And then, here comes Sanctuary. Brauner didn't invent Sanctuary. He has already seen it before, and the concept bled into his painting.
I do agree something relating to 'purification' in general seeped into his subconscious mind, whether this was to do specifically with curing Vampirism I'm not certain if he'd physically seen it or experienced THAT before. At this we can only hazard a guess.
What I will say is that context is very important as I stated with List 1 & 2 above. Ancient Egypt had several 'rituals' and practices that involve "purification". Hence it makes perfect sense for this spell to be in the Egypt/ Pyramid stage.