Firstly, concerning the website – any chance you can make it useable for those of us that prefer to have JS etc disabled?
1. Can I use it as a web server?
You could, but Zeroshell is not optimized for acting as web server.
2. Could I use it as a web server/FTP/sFTP/SSH gateway? (with load balancing)
Yes, you could by using the virtual server section of Zeroshell. In the next releases this section will be improved.