Using Mac mini with an external drive?

I have an old iMac with a 10TB drive. Its now time to update.

My challenge is a storage challenge. We have a lot of photos, family movies, a large music library etc.

We use homeshare so we can watch movies from the main computer on Apple TV's around the house.

We use crash plan as a backup solution as well as time machine.

We have lots of documents etc.

If I choose a Mac mini with a large external drive then is it possible to:

1) Run my photos library form the external drive?

2) Run my TV app with all my home movies from the external drive

3) Run my Music App with all my music library from the external drive

4) use homeshare to that I can view movies and listen to music on the Apple TVs around the house

5) Can I run my email from the external drive

6) Can I put my documents folder on the external drive.

5) Use Time Machine (will it backup the external drive or will it run home and backup the Mac mini internal drive. Can Time machine backup both internal and external drive.

6) Use crash plan for the external drive

Basically have only the OSx on the Mac mini internal drive and have everything pointing to the external drive. What are the exceptions?

Thanks!