Django project structure in production
The reason some people put static files in /var/www is simply that that's where the default Apache configuration puts the DocumentRoot on Debian-based systems. But I wouldn't recommend doing that; much better to add an alias pointing at the STATICFILES dir inside your project itself.
As for permissions, your suggestion of using www-data and adding your users to that group is sensible. The recommendation to put the code under /srv was probably mine in the first place, but I think it's a good idea; it's an easily identifiable location which is probably not used by anything else.
You really shouldn't be using sqlite in production. Install a proper RDBMS; preferably Postgres, but otherwise MySQL if you must. Neither is very hard to configure.
I'm ready to deploy my completely revamped Django website, and I'm trying to figure out the best folder structure to use.  When I had it deployed last time I did it all wrong, even though it was functional, so this time I'm trying to do it the "right" way.  Unfortunately, it seems sometimes like there are too many "right" ways for any one way to make sense, so I'm trying to get some clarity on that.  I'm using a Linode VPS with Ubuntu 14.04 LTS and nginx.  I've been looking through walkthroughs, forum threads, and answered stackoverflow questions, and amazingly, nothing has been able to answer my questions. So here goes.
I'm planning to have the Django root (the top level project root folder generated with startproject) live at /srv/www/<site name>/djcode.  What permissions should I assign this folder, what user should own it, and how should the groups be set up?  Theoretically, someone else will be helping me maintain this project in the near future, so it doesn't seem to make sense that I would chown it to my personal user, even though that was suggested in several posts that I saw.  Would I let www-data own the folder and all the files and then add myself and my future collaborator into the www-data group?  (I'm also very weak on my understanding of how groups work in Linux, so any pointers to clear explanations of that system would also be welcome.)
Backing up a bit, does it make sense for this to be where my Django code lives?  I saw only one answer in a good hour or so of searching that had a suggestion for where the code could live (the rest of the examples had the most unhelpful path /path/to/django/root in place of an actual path), so I'm not entirely sure what is the right thing to do.
Also, I've noticed that people sometimes seem to use /var/www/ for static HTML files, which doesn't make sense.  Isn't the point of /var that the file sizes could be subject to change?  This then begs the question, though, of why we have a separate directory for files of variable size.  I assume I'll want to put my sqlite database file in there somewhere, but where exactly would it live, and what would the advantages be of putting it there?
Thank you in advance!