100% agreed.
I will add Trash. More on this later after I answer other questions.
Yes.
The same way it works with Netflix, Hulu, etc.
Yes.
Mostly TV in my situation. There are 5 adults in my family. Sometimes we watch something together but other times, when people are in their own rooms, they watch on their own TVs.
Now, about the Trash...
I was thinking something like this:
- one person marks a program for deletion
- this program becomes hidden from the library for this one person and is placed in a trash associated with this person (same as the current behavior but each person has a personal trash)
- same behavior for other people
- if it happens that everybody in the family has "deleted" the same program, it will get deleted from the disk after the defined retention period
I also selected "Other" in my vote but now I don't remember why. 
When that comes back to me, I will post about it.