I bet SK has a pretty good idea what’s going on simply by knowing the identities of the commanding generals of those 2 combat divisions parked outside Pyongang.
If they are known Kim loyalists then I’d imagine they are there to purge any would be trouble makers during this period of succession and to dissuade anyone from the idea of a coup. If they are loyal to a particular military faction or another Pyongyang elite - then we may be witnessing a coup.
I suspect that the Army has been calling the shots for a while with Kim as a super-annuated figurehead.
I think that behind the scenes China and South Korea are cooperating on plans for the post-Kim era in North Korea.
China knows the future is with a united Korea with the current South Korean government in control. China wants Korea in their sphere of influence, and they are trying to make that transition as smooth as possible.