Nice 
No MLJ? I'm disappointed. 
Seriously, good work. Your chart matches up nicely with my thoughts on the Golden Age. If you have the character lists in some postable format, could you post them?
Gotta ask: who was the lonely mutant?
My guess would be Namor the Sub-Mariner. Even though he's an Atlantian (or half-Atlantian) and not fully human, Marvel has said that he's a mutant and more powerful than other Atlantians.
There's a fairly well-known guide to Golden and Silver Age characters for City of Heroes called "Doc's Guide to the Golden and Silver Ages of Comics for CoH" While it is an acceptable splash of what the colors and names of Golden and Silver Age characters were, it doesn't get into what kinds of power mixes and origins were more or less common in any of those ages.
I did a little bit of examination of actual Golden Age characters, specifically, if I were to guess what archetypes and origins they had, what the sample would be. I got information on over 100 different golden age characters (defined as "first publication before 1950"). I culled any that had only appeared once or twice. I likewise culled those that I couldn't fit at all into the CoH rules. In addition, I took care to eliminate all "retcon" characters--characters invented in the 1960s or later and back-dated to the Golden Age. At that point, I was left with 89 characters originally from Marvel (sometimes called Timely or Atlas), DC, Charlton, or Quality. Marvel and DC made up the bulk of the sample. I then just counted what archetypes and origins were represented. Some characters could fit two archetypes, so I counted them as 1/2 for each.
This is what I found:
<font class="small">Code:[/color]<hr /><pre>
Bla Con Def Scr Tan
Magic 0 6.5 3 2.5 7
Mutant 0 0 0 0 1
Natural 1 0 1 33 8
Science 4 2 0 7 5
Technology 3.5 1 0.5 0 3
</pre><hr />
As you can see, scrappers, specifically natural scrappers, are extremely common, outnumbering anything else. It should be noted that the lonely mutant was only arrived at by process of elimination--didn't really fit anything else. I'm not going to get long-winded on this. I just wanted to give people an idea of what kinds of characters were common, what was rare, and what seems to have been positively unheard-of in the Golden Age. However, my list is not comprehensive. It can still be used as a very loose rule of thumb if one is considering a new character. For example, when in doubt, a Natural Scrapper (bare-fisted, of course) is good to go in the Golden Age. Blasters mostly came from what CoH would call "Science" or used doodads. Defenders and Controllers were almost always magicians, but tankers pretty much came from across the spectrum, with one exception not visible in the table. All of the Technology Tankers were robots. The powersuit was more of a Silver Age concept. Anyway, this is just to amuse people. Feel free to reproduce elsewhere.