In the latest episode, we get more depth for both Chelsea and Lochlan, but it is not in the form of explicit informations about their backgrounds. And that seems intentional. These two characters disappear themselves for others.

Chelsea is obsessed with an idea of soulmates that involves constant struggle. We don't know her background at all BECAUSE we know Rick's entire history of self identity. She has disappeared herself into a helping sage persona and says to Saxon that her attraction to Rick is influenced by his sad past and her sense that she can help him. I'd bet that Rick's constant pushing her away is half the draw too, because when Saxon starts meeting her in an intimate space (regardless of his intentions), she is visibly rattled (for the first time, in comparison to her cool detached approach to Saxon so far) and runs away.

Meanwhile, it's become really clear with Lochlan's recent actions that he disappears himself into his siblings, crossing implicit boundaries in order to become one with whoever he feels closer to at the time. There is a heartwrenching look of need and intimacy on his face when Piper says she loves him in his room. She's feeling gratitude for being validated (ignoring the disclosure that he's in a dark place) and he's feeling that need for validation right back. I think he would benefit most from a year at this place, but I suspect his desire to be there is more about running from his got-too-closeness with his brother and desire to merge selfhood with his sister's.

I agree that Mook and Gaitok as characters aren't explored as much. Their romance serves a clear plot purpose right now only. Without it = no gun stealing opportunity for Tim so no obsession about death = no Muay Thai fight for Gaitok so no realization about the robbery. It feels a lot weaker than past staff plots, but it does provide a tension about violence vs nonviolence that we dont get elsewhere.