If chat is important to you I'd definitely take a look at Slack in combination with Google Docs. Slack is a very good chat client, but it's the ease of extending and integrating it to your systems that is the real killer feature (imo). When a tool is cumbersome to use (and/or hard to learn) team communication is the first victim in my experience. People simply don't use it, or use it reluctantly and as little as they can. Slack gets this and goes out of its way to make communication frictionless.