Share iTunes Library / Duplicate Items

This is kind of a long question, so I apologize. I'll give my equipment breakdown first.

- iMac 27" 2013
- AppleTV (3rd Gen)
- Drobo 5N

My wife and I share our iMac (two different accounts). We have our iTunes library on the Drobo. I am in the process of ripping our DVD collection to the Drobo and will share it with the AppleTv.

I am encountering a couple of issues maybe someone could help me with.

1. The Drobo I have an "Entertainment" share set up, with subfolders "Movies", "Music", etc. I am putting all of the movies in the "Movies" folder. How can I get iTunes to automatically see the "new" movies (right now if my wife wants to see the new items I added, in iTunes I have to go to Import and select "Movies"). I have to do the same for my iTunes account.

2. When I do the above, movies that I have already imported are sometimes duplicated. If I try to remove the duplicate items, sometimes the "real" file gets deleted (so I have to re-rip the dvd).

3. At times when we open iTunes, we get the message "cannot find the library". To remedy this, I have the "entertainment" folder set to automatically mount when the user logs in. But sometimes this no longer works and I have to reboot the iMac and/or the Drobo and the issue is resolved.

4. I know for the AppleTv to see our iTunes library, sharing has to be enabled. Is there a way for AppleTv to see the iTunes library without having a user logged in all the time/iTunes open?