What does "Arang and the Magistrate" have to resolve before its end in 4 episodes?

"Arang and the Magistrate" is about a lady ghost Arang (Shin Min Ah) trying to figure out the truth behind her death and a magistrate named Eun Oh (Lee Jun Ki) who is able to see ghosts. 

As the drama nears the end, the two characters are getting to the end of the mystery. However there are still 3 questions to be answered. 

Will Eun Oh kill his own mother?

When Eun Oh faced Hong Ryun on the October 3rd episode, he cannot hide his shock at the fact that the ghost had taken the form of his mother, Lady Seo, 

Eun Oh then looks for psychic Bangwool and says that there's a ghost in his mother's body but he is given the answer that he cannot save his mother and simply remove the spirit of Hong Ryun. 

Then on the October 4th episode, Eun Oh finds out that he is the only one that can remove Hong Ryun from his mother's body, which pushes him to the choice between whether he will kill his mother with his own hands. 

Ju Wal, who has found out about 3 years ago, where will he go?

The October 4th episode also revealed the tragic past of Ju Wal. Lee Seo Rim (Shin Min Ah) had died while trying to save her love Ju Wal. 

Ju Wal had forgotten about this thanks to the trickery from Hong Ryun. However, Arang finally remembered what happened in her past and was consumed by her anger towards Hong Ryun. 

Then we saw hints that Ju Wal would also remember what happened and people are wondering what he will actually do once he does remember. 

Will Eun Oh and Arang actually get a happy ending?

There isn't much time left for Arang. People expect that Eun Oh and Arang will not get a happy ending for their romance .

Eun Oh saves Arang, who was once again near death, and realized how she felt about him. However, he knew that she was trying to push him away so he simply wishes her well from afar.

However, Arang felt the same way about him but couldn't accept him because of what it would do once she had to leave.