Download using JP account?
Yep, and you can buy Japanese PSN cards since you can't use foreign credit cards. Although it's a bit of a hassle if you have non-Japanese PSN content you want to play, but there's ways around that too, though I haven't tried it personally.
And back in the day, it was the Sega Saturn that retained the ero bits in games while the Playstation was deemed the "family console", so I'm not sure this has any ero content in it.
