I think David Warwick is similar to Alex in that he is not the brightest star and has always felt like he didn’t belong anywhere, lost in the world, a little hollow inside. Gibb seems to have abandoned her own family but I’m not sure David did the same; he apparently has a special needs son, and claims he tried to connect with JJ because of this. I can see where he would have preexisting beliefs or interests in prepping and “end times” predictions, which led him to Chad’s group. He has a fling with Gibb and they end up marrying, possibly with ulterior motives on Gibb’s part. He testified he didn't fully agree with everything Chad was saying. But he was glad to be included in a group.
Based on his testimony, as well as MG’s, I think that David and MG were meant to act as alibi witnesses for Chad and Lori while JJ was killed. There is simply no other reason why they chose to kill JJ that night. Think about it: MG and David were there for a podcast recording and slept over…why couldn’t they have waited for another 24 hours when they weren’t around? David and MG asked about JJ that next morning when he wasn’t present, and as previously stated David had his eyes on JJ (so to speak).
Let’s assume JJ was killed at the apartment, or the murder started there. Had David woken up from his weird premonition nightmare and walked in on the event, he would be officially complicit and could be scared into silence. Same with MG (who I don’t trust at all but I also believe she was on her way to becoming another victim at some point). But despite this dream they didn’t investigate too hard, so were able to provide an alibi that, to the best of their knowledge, Chad didn’t sleep over and Lori never left her room. They simply woke up to JJ being gone and supposedly with Alex.
MOO.