Yes you can play any region games in any PS4 region. DLC, however What are the differences between the Japanese PlayStation 4 and the U.S. version?.
I've seen some online stores (e.g. play-asia) selling Asian version of 3DS Some threads appear to claim this version can play US games.
Well Asian Versions of certain games come with English manuals (depending on the games), but I believe the cases and manuals are cheaply.