I have to say I am intrigued.
My take on Pentecostal History from a more spiritual point of view is this:
God poured out his spirit in the United States for various reasons. TW Barnes (no clue where to find the quote) once said that America was birthed for three things 1.) evangelizing the known world, 2.) supporting Israel, 3.) policing the world (all three paraphrased). I generally agree with that. I believe that Azusa was significant in the fact that it formed a movement of spirit filled brethren that were seeking truth. Those seeking truth genuinely found it.
Out of those brethren were a called out and separated group of believers. Those who got the revelation of the Oneness of God and the Baptism in Jesus Name. It was a group separated from the RCC and it's trinity doctrine.
There was another (larger) group were men simply fascinated with the tongues, ecstatic worship, and demonstrative praise. They came from two backgrounds (as all Pentecostals did) the Calvinist/Reformed background and the Wesleyan Holiness background. Though they embraced the tongues, because they really had no heart for truth they kept their doctrines that's why we have two "branches" of "Classical Pentecostalism" that reflect either the Calvinist/Reformed ideals in their doctrine (Higher Life/Assemblies of God) and the Wesleyan/Methodist ideals (COGIC, Church of God Cleveland, Tennessee). These two "branches" never really intended to leave mainstream Christianity, just to adopt this new phenomenon, which they saw as the "power" described in
Acts 1:8. In a sense it was almost a thirst for power. Now they could heal the sick, prophesy, perform miracles. Yes for a while mainstreamers called them "demonic" and they were marginalized but all along THEY worked hard in the 70s and 80s to find acceptance in Mainstream Christianity. Now from the Assemblies of God to the COGIC Pentecostals are at the forefront of the new "ecumenical gospel", which is why Kenneth Copeland is running to go see the Pope.
I say all that to say this, from the beginning I believe Azusa happened to birth a single and separate church that would preach truth in this generation. What you've brought to light in some ways confirms this. God was opening people's eyes way before 1913. I'd imagine eyes were opened in 1906, we just didn't hear about it. In matter of fact while I was writing this long (sorry response) I just remembered: there is a book out by Charles Parham where he stated that he baptizes in the name of Jesus Christ alone. I've read it myself I will try to find it. I don't know when the book is written or if it was written prior to 1906. However this article suggests that Parham was Baptizing in Jesus Name in 1901:
"practiced water baptism by immersion. Charles Fox Parham began baptizing in the Name of the Lord Jesus Christ around 1901."
https://oldlandmark.wordpress.com/gl...ostal-history/
I have to find the book and see when it was written so I can confirm this, but I'm sure at least it was written before 1906 because Parham lost a lot of his influence in Pentecost after that time because of his supposed sexuality and issues with "interracial churching". I'd imagine if the above article is correct and Parham baptized in Jesus Name as far back as 1901 than William Seymore probably knew a little something about the "New Issue" before it was "new".