It can have it's own members area look if you setup a membership for it. It will have it's own look, however, the members area would share the domain from the primary site that the piggyback is attached to.
A. The system comes with these added by default.
Add/Remove this code from /uploads/adminpages/misc/body-bottom.html
in order to show/hide the icons.
Upload any custom icons to /uploads/images folder using the filenames below:
NOTE: The help icon can be turned off from advanced features and if it is turned off there then it will not show regardless if you add ~helpicon2~ or not
Yes, there is a page which you can make available to your members allowing them to import contacts one at a time.
The page is located at: yourdomain.com/admin/contactadd
You can control how many contacts a member is allowed to add through this page per a day in advanced features.