Item 2: Are you on https://panel.dreamhost.com/index.cgi?tree=vserver.settings& ? This is a separate page for your VPS.
3. PageSpeed is hit or miss :/ If you're using OURS the fastest way to make sure it's working is to view page source and see if it compressed things.
4. Nope. You can switch back and forth very easily via ttps://panel.dreamhost.com/index.cgi?tree=domain.manage&