There seems to be an issue with the social connector package. The team is unable to login to Facebook using out of the box cloud connector. Team will update you about the second package in a day or two.
Rama, in all cases the forms are still pre-populated the same way. Just the XML will change depending on which model you choose (xfa, schema, no model). Ideally you'll use a schema because if you move fields around in the adaptive form, you'll have the same issue that you had with Designer where the xml output will change based on the field location.
That said, one of the easiest ways to experiment with prepopulating is to create your form, then submit your form to your custom service and look at the structure of the XML submitted. Then, re-create that structure and populate the data node in your pre-fill.
In your post.POST.jsp, use String formXML = request.getParameter("jcr:data"); to get the string value of the data submitted.
In your profill.jsp, use the reverse, slingRequest.setAttribute("data", formdata); to populate the data of the form.