Do we know who exactly wrote all the Clancy letters/lore IRL?

I was super pumped to get the Clancy journal for Christmas and so I'm enjoying reading over all the letters written by Clancy from dmaorg.info in printed form!

I know there's lots of debate about how related Tyler and Clancy are in the story (one person? two characters?), but I'm wondering--outside of the story, in real life, who has been writing all this? Is the story a group effort? Or pretty much just Tyler's creation? Are the letters in cursive handwritten by Tyler (as in, are they actually in his handwriting), or transcribed by someone?

I don't know if we know any of this for sure, but I figured if it is known, someone on here can tell me! Thanks!