Does furniture work on girls that are trapped in the dungeon and not yet recruited? Also how does the whole torture vs gift thing work anyway? Like does the outcome change? Does doing both just give me a flat double speed to completion?
Furniture does not work on girls still in the dungeon.
The way gifts and torture works is:
Torture gives submission and for every 4 points of submission the girl gain 1 affection at the end of each day. Submission caps at 10 so when you have 8 submission on a girl doing more won't really speed it up (The preffered torture for a girl gives 4 submission)
Gifting gives attention happiness. And that works exactly like submisison, as in every 4 points is 1 affection and it caps at 10. So you can at most earn 2. Attention happiness does however get lowered by 1 each day so you need to maintain that.
You can never earn more than 4 affection per day, even for girls out of the dungeon, that's just the cap. Dungeon girls starts at 1 affection and can be let out at 21 affection.