Hello there,
1. There won't be a gallery or "card collection", this is not a full "dating sim" per se, would also mean to "create" more information since not every character has everything listed and doing this for the roster would be a lot of work.
2. This won't be a feature, is has already been explained. As you said yourself the player is the one wanting to interact, the only option were this was "kind" of obligatory was Phoenix for the athletic stat and is why there's an option for her not to spot you.
3. Having specific days for the girls is a way to have something special in specific days, you can always find them at their respective places, it shows they do other things than just wait for mc to call them for sex. This will not be integrated.
4. The game gives you the choices of routes, every route has content, that's what gives replayability to the game. If a route already tells you what you get and what you lock, there is no surprise nor really feasible. And by choosing a route you should assume the other is locked. Sofia is a good example, you can do this from really early, having it says "oh this unlocks Emma at the farm" just ruins the fact of the player discovering the farm later on, and its really clear what happens if you tell the corrup governor a police woman is hunting him down.
5. There are no plans to add more attributes, most attributes are used already for either flavor text or specific things.
6. This is planned to be revisited after the full game and also to verify all needed pictures appear.