Setup a demo System from a existing website & build a deep link plugin

First Part: Setup the existing website on our subdomain for the demo installation of the live website. Test the demo website with all features of the live website. Update the Typp3 Version to the newest Version and test again all featues of the website. Second Part: We need a plugin / extension for deep links. The existing website has an user login. So each user must login to see the whole content of the page. We want to send monthly newsletter to all user and link into the content behind the login. So the user first would click on the link in the newsletter. After that the Typo3 System check, if the user logged in. If not, the user must first login and after the login the system automaticly push them to the target from the link in the newsletter. The links must look like this: [login to view URL] The paramter always is "id=XXX". The paramter ID is the target site. The link to the login is: [login to view URL]