Ghost Trick?

Depends. I haven't played Ghost Trick. What's the gameplay like?

tbh i dont think ghost trick matches what youre going for, its like obra dinn only in that you see characters' final moments and use information from it. gt doesnt have sifting thru data or involve deductive observation in a similar way. ironically enough i think ace attorney would be more fitting bc you look thru your evidence accrued and use reasoning to decide which is necessary during key moments, but that and ghost trick are both in the AVG tradition where mystery drives the player to know a games characters than to explore a games spaces, so maybe that wont be enough for a game /entirely/ around careful observation of spaces (as data and as environmental).

a hand with many fingers ought to be on this though

Wow, I completely forgot to put A Hand With Many Fingers on here despite it being the game that reminded me to make this list!