When I review this case I am struck by how little we know about Tylee Ryan's personality, state of mind, and relationship to her mother, stepfather (CV), and step-brother (JJ). Yet these are typically things that are examined by law enforcement and the media when someone, especially a minor, goes missing.
The central question in my mind is: to what degree did Tylee share Lori's beliefs? I don't seem to find any interviews with Tylee's friends or teachers that would shed light on this.
It does seem clear that Tylee was comfortable in her mother's company. When Lori cleaned out CV's assets in Jan 2019 and went walkabout for two months, Lori took Tylee with her (including to Hawaii, by some accounts) and abandoned JJ to the care of CV. If Tylee was under duress during this period it seems likely that she could have contacted someone for help.
Both Tylee and JJ apparently witnessed the shooting of CV by Alex in July 2019. Cops arrive, Alex and Lori are interviewed, but we have no information on who was watching or talking to the kids.
At this point Lori is in Arizona and free of CV but has Tylee, to whom she is presumably close, and JJ, who is now excess baggage, to worry about. She discovers that she is not getting a million bucks from CV's insurance. Behavior during August 2019 is erratic. She enrolls JJ in his old school (to get him out of the house?), and dumps his dog. And during this month Tylee is doing what?
Lori gets evicted at the end of August and moves to Rexburg with the kids. Tylee goes along, again apparently willingly. JJ is enrolled in school, and Tylee's activities again appear to be unrecorded.
Now we have the trip to Yosemite. Tylee goes along, apparently willingly, and is not seen again. JJ returns with Lori and Alex to Rexburg and attends school for two weeks, then is pulled out and disappears. Whatever explanation Lori gave to JJ for his stepsister's disappearance seems to have been adequate because there does not appear to be any evidence of JJ engaging in serious acting out or other post-trauma behavior.
On 1 Oct, free of both Tylee and JJ, Lori rents the storage locker and the case takes a whole new arc, Lori and Chad (and Tammy and Melani and others) instead of Lori and Charles (and Tylee and JJ and others).
So we discuss the second arc in detail, but in doing so we seem to lose sight of the multitude of questions surrounding a central character in the first arc: What about Tylee? Did she share her mother's beliefs? What was she thinking and doing while all this was going on? Did she talk to anybody about all this? Was there a breakup between mother and daughter that caused Lori to sever what in the past had been a very possessive relationship? IMHO these are more important questions that what was going on with Melani and Ian and other peripheral characters. YMMV.