There isnt much there.
For facts, please look at the covers of
Action.Comics and Detrctive Comics.
Superman does not appear on the cover of early Action comics only issues 1, 7 and then 13 onward. A year after Action.1
If they knew Superman was a hit early on, he would have been on .earlier covers.
Similarly Batman is on.the cover of Detective 27 then 35 onward, about a half a year later.
Robin however appears on.issue 38 and every issue afterwards.
The story about Robin is that when was introduced sales double. They were reluctant to use the characters. Given lead times in.producing an issue, there was no way they would have known about sales that quickly… yet he is on the next cover, unlike early Superman and Batman.
The covers shows they were enthusiastic about Robin even pushing the Dr Strange story from issue 38 to Batman 1. That story was jarring to the reader because it had Batman kill.
The download you gave reflects that.
I think Jerry Robinson was being funny when he said the name of Robin came from his name.
Robin was included in Batman according to the download as a Dr Watson. If so why is he a kid? Obviously to attract kids but your source doesn’t say so.
The only other thing the download says is that nobody wanted to.publish Superman. Even though Siegel and Shuster were working at what would become DC for years, nobody would look at their new character.
Why are you conrinuing to research this?
You are not looking at authoritative sources, just popular accounts.
Looking back at the Batman Year One page you showed us, I am appalled at thr ignorance of the editors of that work as if Frank Millet started the new Batman and O’Neil and Emglehart never worked on and created a. new version in the 1970s.