Caleb, 5th video will unlock Lt. Colton. Someone had a hard time understanding this sentence so here is a more detailed version. You enter Caleb in the search video. Than you choose the 5th video , don't need to watch it completely just press close once open. Press unlock and it will unlock lt Colton.

Now search for Ruth, 2nd video will unlock Ruth.

Now search for Cistern, last video will unlock Heather.

Now search for Tooth, last video will unlock Natalie

Watching the last video of Natalie will unlock the option to accuse

Keep in mind this has to be in order, you cannot unlock natalie before unlocking heather etc

You need to close the game between each ending or you won't get the achievement. So do one ending, close the game and reopen it before doing a different ending. Or else you won't get the achievement

Lt. Colton and Heather for Main perpetrator achievement

Caleb, Ruth and Natalie for laughing in the dark achievement

Everyone for the last achievement

"Hobby" give you eye of the beholder

"Necklace" give you detail matter

I believe "dead dog" give you eternally yours but correct me if i'm wrong

"Glove" give you If the glove fit i believe but again correct me

"F"l"uck" without l give you bad word

digital sleuth is unlocked with Fyre Festival, thanks to the two user ( allison wonderland and biotic geth prime) in the comment pointing it out