With respect to the off topic conversation - have you considered an off topic forum / area? I've seen this successfully applied on many sites - Some are a no rules anything goes forum which is clearly labeled as such - Those who don't like the tone of conversation simply don't view it. Off topic posts in other forums can also be moved there (although Orca currently doesn't allow this).

The area can also be password protected, and a minimum number of posts required before entry is allowed.