I think its just too much time between updates (I'm very thankful to the scanlators don't get me wrong), Eliza got swatted back in chapter 61 during the group attack and has been resting since then.
We've seen that memory erasure can knock people out as a secondary effect whenever he uses it...
I think it refers to him being willing to take part in the lover's abyss. Since he wanted to do it at the start of the series but changed his mind and kept telling Nagi to live, but now that the knowledge of Mao has 'tainted' him, he seems like he's going to go through it with Nagi
No, Yuko tells Esemori that he's come back to the town 3 times now.
1) Pretending to be Esemori's relative (which conceived Reiji)
2) At the start of the Story
3) RIght now as he is dying
Esemori reacts the way he does because he thought that Yuko didn't recognise him the first time. Hence...