Ya it happened during Arkham War.
I don't think anyone will replace Bruce. Tom King seems to be interested in writing stories that test the character's ability to deal with mental and emotional stresses, and I think that's what he's doing here with Batman. Ultimately I think Batman's triumph will be in overcoming the emotional hurdles thrown his way.
So far the evidence has not pointed that way at all. Unless you read other books who show that but not in tom kings story
Ah really, that I didn't know about. Though honestly, considering how little of a connection this book has had to all the other Batman stories currently being told it would seem out of left field to suddenly have something like The Batman Who Laughs play a big part in King's story.
The most I could see it connecting to is maybe Doomsday Clock, since he already had both The Button and now Flashpoint Batman returning, plus all the weird "Batman & Catwoman split memories".