As for the "did we solo? Were we in a group?" I'm content with the reasoning given (in HW, I think?) that the answer to that is "are you? Aren't you? Who knows?" unless made obvious such as Prae or Hades in which you can see the other players as part of story-centric cinematic.
What reasoning would you be referring to? That could make for a good addition to the document!

Other than that I don't have too many nitpicks aside from some inferences regarding the echo and adventurers not being likely to have it and lack of other warriors of light (though I know of only one explicitly named off the top of my head) Maybe I misunderstood though.
I assume you're talking about when I point out Urianger's changed line? There are no references to other warriors of light existing at the same time as the current single one. There have, of course, been many others in the past, like those who were active during the leadup to the 7th Umbral Calamity, Tenzen, and Saint Ajora. But the player's WoL is the only one currently known, which is undoubtedly why Urianger's line was changed.