Hello there,
1: Negative, Starmaker won't really go into extreme kinks and fetishes, that's more of a Roundscape thing. While Starmaker features some things like you mentioned, it won't go further.
2: There won't be a gallery for scenes. At most, a gallery for non-repeatable scenes could be done, but this is a maybe. Mods are allowed and this can solve the gallery issue.
3: The studio while it can be expanded, is a daily activity, it has some scenes for each of the invited guests, the pills modifiers for Anna and her regular scenes + the clothing collection. There might be some extension of the content there, but it won't be a huge thing, since is mostly a once a day activity and this won't be changed.