1. No. But there are subtitle and footnote sections to add description of your chart properties at an overall level.
2. Maybe possible depends on what parameters to want to pass. generic query strings will probably need to use a variable extension to store your current selections in an appropriate format for query strings.
3. No not at present
4. No sheet name is currently text only although you can upload an image for your sheet in the properties or an image in a text box you could position in the top left hand corner of your sheet underneath the name.
Thank you Andy for your reply. It helped me alot. Any way, I need little clarification on my 2nd question, like passing parameters. Could you please post any sample qvf file on this. I heard that we can't create a variable in UI Level.So i am wondering, how can we pass parameters to URL.