Hello there,
Good that you are enjoying the game. There is 0 intention of abandoning the game, but having said that, the last update will be 2.0
1. This won't be done. It would be a huge modification of the current system.
2. No plans to do this, as is not really a feature that the game aims to do.
3/4. Could happen to add other locations but it's unlikely, the casino is a no for that kind of minigames.
5. No more vacation spots will be added.
6. Has been advised before, if a gallery is made, it will only be for non-repeatable scenes.
7. Some npc have house locations, it is unlikely to add more as there's a lot of npcs.
8. There is plans to tie a purchase of a house to the endings once those are reworked.
9. Negative, no other girl will have a Starmaker page and at most, only 1 more character will join the studio (after a quest for it).
10. Anna's clothes won't be customizable.
11. Most of those have routes, characters in Starmaker have personality so not everyone is fine going into a relationship with mc.
12. There won't be changes to existing characters.
13. A solo route for Japan is planned. Its undecided how it will be handled but Samantha nor Alice will be included.
14. Unlikely to happen as the "phone" is basically a skill to call Anna for outdoor pictures, not an actual mechanic/system of the game.
15. Could happen as an Easteregg but is unlikely.
16. There are chances but always keep in mind new characters are kept to a minimum as the plan is to increase the current ones content.
17. There won't be content for these characters as those are raffle winners's requests. One could request for winning a raffle, but those are stopped.
18/19. Maybe, but have in mind the invitations are for "relationship" girls.
20. Won't happen, Mc will remain mostly "slightly visible"