Actually if you buy the first game physically, the second's content will be discounted as DLC on the eshop.
Japanese prices are as follow:
Â¥4700 game
Â¥1852 other game's content as DLC
Â¥1852 3rd scenario as DLC
If you buy DIGITALLY there will be only one version downloadable. In this version, the game remains the same until chapter 6 at which point the player will have to make a choice that cannot be undone. This choice will decide whether you go on one version or the other.
There will also exist a limited edition of the game that will contain everything.
Too bad I can't waifu myself cuz FeMC is right down my alley.