As ProThoughts said features are frozen for 1.8 now (unless someone else develops an amazing, vital feature for Q2A in the next 2 weeks). But to answer your questions:
- This would be a nice feature but it would take a lot of time and I don't think it's worth replicating what other tools already do (e.g. phpMyAdmin). But this is something that could be done as a plugin.
- I did answer your other question, this is a very niche issue that doesn't apply to 99% of your visitors.
- This is not something that can be solved in Q2A core, and again is a micro-optimisation only for high-traffic sites. Here's a good article about this subject, which even suggests that using a CDN for a low-traffic site will slow your site down.
- There is a plugin "Online User Count" listed on the add-ons page. But the download is not working right now for me. Maybe someone else has the plugin? Edit: there is another plugin here that may work.
Note that 2 & 3 can be solved using a custom theme or a layer plugin that overrides the head_script or head_css functions and rewrite the URLs to the files on your CDN.