You'll get this trophy at the end of the DLC no matter what choices you make. This is a guide to inform you how you get people to choose yes/no for the group decision at the end. Depending on what happens in Season 2, you might want to change these choices. (Now season 2 is finished we know what will happen, but I will keep this guide spoiler-free about that season)
Just to be sure nobody reads anything they don't want to read, I've spoilerised the information. Take note that there are a couple of spoilers about what happens during individual stories.
I take zero credit for this information, I found it on the Walking Dead wiki after I finished the DLC to see what I should do to change some people's opinions.
*** Spoiler - click to reveal ***Who joined Tavia and who rejected?
Depending on how you played each survivor in their own stories, will determine their decision whether to stay at camp or go with Tavia.
-Vince will join if he shoots Danny's ankle off.
-Bonnie will join regardless.
-Russell will join if Tavia tells him there may be people he knows there, hoping to find his grandmother.
-Wyatt will join if he stays in the car, or Tavia tells him there may be people he knows there, hoping to find Eddie.
-Shel will join if she and Becca leave the Pitstop in fear of Roman finding them, or Tavia tells them there are people of all ages at the community. Becca will also join if Shel does.