[The Australian Panther]

'Things Everyone Forgets About DC’s Dr. Occult'
https://www.cbr.com/dc-doctor-occuilt-forgotten-facts-comics/

1/ He even predates the actual name “DC Comics” having been first published when the company was called “National Allied Publications” in New Fun Comics #6.
2/ Dr. Occult was created by Jerry Siegel and Joe Shuster, the creators of Superman.
3/
'Dr. Occult is cut from the hard-boiled, square-jawed detective paradigm with supernatural elements added. His reliance on a trenchcoat, fedora, and suit in battle has become a staple for the “mysterious male magician hero.” So much so, when Occult, John Constantine, the Phantom Stranger, and Mr. E gathered to question new mage Timothy Hunter, Constantine dubbed the quartet “The Trenchcoat Brigade.”
4/ ' the case could be made that Dr. Occult is actually DC/National’s first caped superhero instead of Superman. Although, Occult’s caped appearance didn’t appear in a National Allied Publications book nor was he called Dr. Occult. The character appeared in Centaur Publications' The Comic Magazine #1. In this story, he was called “Dr. Mystic” and wore a cape and flew. The story, called “The Koth and The Seven” was continued in DC Comics More Fun Comics #14-17 with Dr. Occult, so the first story was considered canon.'

Link to the book: Dr. Occult Complete Collection

[FraBig]

Given that it's an article from CBR, I'm not surprised some of those facts are inaccurate or reported in a sketchy way...
Luckily, by reading the compilation, every doubt can be cleared:

3/ 'Dr. Occult is cut from the hard-boiled, square-jawed detective paradigm with supernatural elements added. His reliance on a trenchcoat, fedora, and suit in battle has become a staple for the ?mysterious male magician hero.? So much so, when Occult, John Constantine, the Phantom Stranger, and Mr. E gathered to question new mage Timothy Hunter, Constantine dubbed the quartet ?The Trenchcoat Brigade.?

Actually, most of his adventures feature him without trenchcoat or fedora: he was usually dressed in the normal fashion a grown man in the 1930s would have dressed, and the fedora and trenchcoat style was present in just a few of his stories; it wasn't a mandatory attire for him to wear nor an iconic trait of his character during the Golden Age, it just became a thing in his modern DC appearances (after he was brought back by Roy Thomas).

4/ ' the case could be made that Dr. Occult is actually DC/National?s first caped superhero instead of Superman. Although, Occult?s caped appearance didn?t appear in a National Allied Publications book nor was he called Dr. Occult. The character appeared in Centaur Publications' The Comic Magazine #1. In this story, he was called ?Dr. Mystic? and wore a cape and flew. The story, called ?The Koth and The Seven? was continued in DC Comics More Fun Comics #14-17 with Dr. Occult, so the first story was considered canon.'

This is not exactly true: yes, the story arc in which Dr. Occult wears a cape starts in The Comics Magazine #1, published by Centaur, but in that specific issue he doesn't wear a cape. He will wear a cape in More Fun Comics #14 and then fly while wearing it in More Fun Comics #16, both DC/National publications. So the claim that he's the first DC caped crusader (pun intended) could actually be made.

[The Australian Panther]

I'm curious that the question marks in the texts that show up when the AI questions punctuation, are not present in my original post, but there are several in your posted quotes. Odd.
Yes, it's from CBR, but I prefer an alternative from Wikipedia when I can find one,  since thats  not always entirely accurate either.

Good points, but I just think they were saying that, because in some of his early adventures he wore a trench coat, he was later seen as a template for trenchcoated magicians.
I have stared reading the collection, but I hadn't realized that there were so many stories. This must be one of your biggest archives. Well done.   

[FraBig]

Thanks! Yes, the appearances were many (28), but luckily 1930s stories didn't have many pages, never more than 4 or 5. A lot of the early appearances consist only of 1 page.

The collections about Captain Triumph (a Quality character) were much more challenging because he had a total of 36 appearances and they even consisted of multiple pages, like it's usual for 1940s superhero stories, especially from 1941 on.