I don't use Spotify so I can't comment but regarding FLOWER FLOWER's discography blocked outside of Japan , I'm not surprised
It's a Sony thing so it's hardly surprising . Artistes under them such as UVERworld , SID , Hirai Ken & etc also have the same problem which I feel is really annoying
That's why the past YouTube videos that FLOWER FLOWER posted on their account in the previous page of the thread , I decided to rip & upload them as I'm able to bypass them even though I don't live in Japan myself
I don't know why purpose this serves though 

 but Sony fails to understand that there're so many people outside of Japan who're willing to pay & listen to their managed artistes , not just in Japan alone 
End of the day don't they want to make more $ ? I don't get it