Sorry for the very late reply, but you deserve some sort of answer/feedback:
1) As I've already explained, I'm not that big of a fan of repeatable events - especially not if they force you to grind something. Therefore, (repeatable) cabin events will most certainly not influence affection points. But I'll probably add some wholesome feel-good events in the cabins. At the moment, I've only implemented a short swimming event with Pirlia. 
And there will probably be no "Let's-Fuck-Button" in the cabins since I want to keep sex scenes in the main events and the RNG-shower.
I'm very unsure about the lore drops in cabin-talks... First of all, I've written the in-game lore-wiki for this purpose. As soon as a topic is mentioned in story events, a wiki article will be unlocked/updated. The cabin lore talks could be used to convey non-essential background information. For example, Ladira's big 500-line monologue about the Veludran noble families in 0.1 was a little bit of a mistake in retrospect. This monologue would have been perfect for what you suggest - especially since we'll probably only ever meet 2 out of the 5 mentioned families... But the problem is, if I make these lore dumps optional, I have no way to make sure, readers/players will have the necessary knowledge to understand further events. For example, the mentioned ladira_medbay_01 event is a requirement for every event, which needs a baseline understanding of Veludran nobility or knowledge of the Cerser family in particular.
Additionally, Sarlé is probably the only one, who would tell you her whole unbiased backstory from day 1. I think it is way more interesting to get the girls' backstories bit by bit while getting to know them better and better until they open up. But of course, the best way to show a girl's homeworld is boots on the ground on said planet. So it's very unlikely I'll implement such a system.
2) The problem with designated persons at certain times is, that I only have 4 slots for 10 persons, when I stick to day-cycles. I maybe could implement a week-cycle for showers while the rest runs on day-cycles or I could let one girl break out of her normal routine by random.