when league ends....

I didn't play in the last league, can someone explains what happens when the leagues merge?
Specifically:
1) How does PoE determine which hideout I get, the league or perma-league?
2) Do the decorations/reputation get added together, or do I only get the gretare of the two decorations/reputation?
3) Does the master xp add, or only the greater, if not level 8?

Anything else I might have missed? Thanks.