I think I was kinda in the same boat as you.

In theory, I loved the fact that if you wanted to check, the game would tell you when you theoretically had enough information to identify one of the crew or passengers, so you knew where to focus your thinking. But I got stuck on some characters who seemed to me to be implied or hinted, but for whom I didn’t think I had positive proof.

I eventually got tired of continuously reviewing the same scenes over and over, looking for some detail that I had overlooked, and read a walkthrough to find out what I was missing. It seems that I hadn’t missed anything, and “an educated guess” was the standard expected by the game, not “definitive proof”. But I was burnt out with the game by that point and stopped playing.