Hello there,
the picture you saw is related to one of the kinds of endings being added. The player will be able to purchase a new house and have different combinations of characters to invite live with them, no there is no "all girls" with Mc ending. This is only for the endings with the purchable house, the current house in which the game takes place wont change and you wont be able to kick Josef and Adrian out in exchange to inviting others.
In regards to Anna receiving more scenes, she always does as she is the main girl of the game. There will be more sharing as well as solo content.
River does have quite some content, more than even a good amount of girls. It's just like with Samantha, most his content is shared:
- Bedroom solo/share with Josef.
- Park bathroom solo/shared with Phoenix/scene with Adrian.