This week Brett and Alice are breaking down the timeline from August 27, 1998 through January 12, 1999. They cite Hae's diary as a source. They don't mention where the rest of the information is coming from, but it appears they are working off of this Reddit post for pretty much the entire episode:
To binge the Reply Brief series ahead of the main feed drops, you can JOIN OUR PATREON community at the $5/month level. The Patreon series episodes are 8 weeks ahead of the main feed. When you join Patreon, you'll also get all of our episodes ad free, and an hour of Patreon exclusive video content every week.