There's nothing more helpful than an extended video of a player's unedited thought process. I'm gonna admit that I knew from the start that making any kind of vertical slice for this game was going to cause severe problems for playtesters just because of how much context a player needs for it to even be playable. What you played is a mechanics showcase, not much more at the moment, and you did an amazing job poking at everything to stress test the gameplay. I watched the video from start to end. Your patience is inhuman.
In the full game the actual long-form investigation is going to be merged with this moment-to-moment gameplay that you experienced. The junkyard ledger needed a lot of forced nonsense just so that it could be solvable within a single location. Because of that the game is still missing the core of its experience which is the player's initiative, and following leads around - something only possible in a larger-scale demo.
The entire interrogation aspect is also still absent.
The answers to the scene section lock in twice - once when ten are answered correctly (which exposes the wrong ones up to that point), and once when everything is input correctly. I don't state that anywhere and I don't indicate in any way to the player that the lock-in happens at the midway point. Wanted to test how obvious it is when the game draws no attention to it.
I understand the shortcomings of the single-level-demo format, so good work on sticking through it to test out the mechanics.
SOLUTION SPOILER
Blondie is a male nickname. Probably the biggest "fuck you" I did to the player's logical guesswork within the demo.
There are two Charlses. Both of them are involved in the answers. You got everything correct using the intended thought process. Only Blondie and ??? are wrong.