I don't think sleeping in the other houses reduces your family's affection, but I've never tried, so I'm not sure.
You'll have to try yourself and find out.
No, sleeping in your vacation house doesn't change anything, but that's different from not giving them any gifts.
Their affection for you decreases if you don't talk to them or choose to give them presents every morning for a while.
We're not supposed to buy each other's love people. It's wrooooong. (|)8 )~