Hurdles to clear while chasing unification by absorption

Considering the gaping civilizational divide between North and South Korea, what is the most realistic pathway toward reunification? It is currently unrealistic to envision reunification occurring with the North Korea’s present leadership, and therefore it can only happen after the collapse of the North’s hereditary dictatorship. From a logical point of view, it could be acceptable for a different representative government of the North Korean people to enter into an agreement with the South to unify, but that remains a remote possibility. In fact, the prospect of a brand new government stably pursuing unification is a very low probability event. Accordingly, the viable option remaining is unification by absorption.  
 
Even in the unlikely event that the present regime is replaced with another government that is either similar or one that attempts to pursue opening and reform, unification by any other means besides absorption would be an extremely difficult task. 
 
The most likely scenario is that unification by absorption occurs before a new political force or regime is formed. Even if an interim government is formed in order to facilitate the process of unification, absorption is still the most likely method. 
 
In terms of implementing reunification by absorption to achieve a single sovereign state, the two principle challenges will be: dealing with the North Korean military during the transitional period, and convincing China to recognize the sovereignty of the unified Korean state. Even if some form of North Korean government exists during this transitional period, it will be essential for the South to have ultimate control over the North’s military. Throughout this process, South Korea must maintain the stability of its Southern state, economically and militarily. 
 
Failing to successfully absorb the North could lead to open conflict. North Korea has complicated divisions of power. It is unclear how Pyongyang’s politicians, bureaucrats, and commanding military officers will respond during the confusing early stages of a transitional period. Nations like North Korea tend to be unpredictable during regime transitions. The danger exists that an ambitious political force could come into power, decide to protect their base, and refuse to cooperate with the South.