Some of your questions can be answered but some imply implementation of additional functionality.
Ok, now step by step.
1) The common site title can be changed in "inc/header.inc.php" by changing the value of the "$site['title']" variable. If you need to change titles of specific pages, you need to edit the corresponding php files and edit the "$_page['header']=" statements in them.
2) You can edit the meta tags in Admin Panel -> Settings -> see more Meta Tags
3) The "Invite a friend" functionality can be changed in "tellfriend.php", and its layout - in "templates/tmpl_uni/page_29.html"
4) The answer to this question can be found here:
http://www.boonex.com/trac/dolphin/wiki/GenDolFAQs
5) I suggest you to install "Firebug" extension for Firefox to determine which CSS files need to be changed to bring the result you expect.
You can download Firebug here:
https://addons.mozilla.org/ru/firefox/addon/1843
6-8) This is not possible in the default Dolphin functionality
9) Users can't change their profiles this way, but you can use transparent .png files as boxes backgrounds on the profile page. You can use Firebug to determine which CSS need to be edited.
10) There's no such possibility. You can allow/disallow some actions only for memberships. In your case you will need to create specific memberships for every member :)
Some of your questions can be answered but some imply implementation of additional functionality.
Ok, now step by step.
1) The common site title can be changed in "inc/header.inc.php" by changing the value of the "$site['title']" variable. If you need to change titles of specific pages, you need to edit the corresponding php files and edit the "$_page['header']=" statements in them.
2) You can edit the meta tags in Admin Panel -> Settings -> see more