I know with all the info that is out there, it is easy to speculate that this divorce and RO indicates TH had something to do with Kyron's dissappearance. But just for a minute ponder a different scenario.
TH has been becoming more and more mentally wore down by all the attention, questioning and 2 poly's, So let's say Saturday after her 2nd Poly, she did not do well on it she is at her breaking point, she goes home and tell KH that she is done, ready to end it all and thinks it would be better if they were all dead, threatens to shoot and kill all of them including herself.
KH contacts police, (1st call about Threatening) They respond, she seems unstable. KH is advised not to stay there. 2nd 911 call about custody could be KH calling back to see if he can legally take baby or could be TH calling them to see if there is anything she can do because he left and took the baby.
KH then files for divorce and RO because she has threatened to kill him and the baby.
IMO TH is somehow responsible for Kyron's dissapearance but not without a reasonable doubt, I just wanted to put this out there because there is always a flip side to every coin.