MOO and speculation
My guess is that Chad and Lori are in Laie, Hawaii, an old LDS city of refuge and the home of approx. 70,000 LDS members, several stakes, 2 temples, and BYU-HI. And I don't think they plan on ever returning to the lower 48 (not to live/reside anyway).
Sadly, I think the children were either left with a cult member/family/group in ID, UT, or AZ, or were otherwise disposed of by AC sometime after 9/24 (and probably between 9/24 and 10/2) in one of those same states (also a slim possibility in NV). While this is pure speculation, we do know that in Jan '19 Lori reportedly told CV that she didn't want to have anything to do with the children anymore. The children have disappeared.
I don't know enough about state and federal laws to opine on whether Lori's leaving the children in the care of a cult member/family/group is a crime for which she could be prosecuted and extradited. I do think it's possible that TD's autopsy results (specifically if her cause of death is found to have been from poisoning) and other evidence found in that investigation could lead to charges being filed against CD, which could result in his extradition.
I am curious to see what they learn from AC's autopsy results (again, specifically whether his cause of death is found to have been from poisoning), though I don't think the results will help locate the children. I personally think AC committed suicide as a result of his involvement in some (or many) of the bizarre incidents that preceded his death in this case.
More pure speculation (hopefully not over the line, as I don't want any speculation on my part to hinder or distract from any investigation or sleuthing) but it would be especially interesting if it turns out that not only did both TD and AC die of poisoning, but that they died from the same poison.