1. i would like to know whether the above configuration would work with just 5508 and MS Active directory
Yes, you would need to configure an LDAP server on the WLC pointed to your MS AD, binding properly. Then, make sure your L3 authentication priority is configured to query LDAP first. This works pretty well in a L3 web-auth scenario, but is limited when using LOCAL EAP
Explain more on what you are trying to achieve. Portal pages are really meant for guest access, but not always used for that purpose. I have had created portal pages tied to AD credentials for customer specific purposes. However, I have used Radius servers like NPS to do this. This way I can determine what groups can use their AD credentials to access the wireless through a portal.