Some of the associates on the team are really nice & encouraging, they will recommend you for a extension if they like your work & general ethic. However, a PPO without a call-back (which you are supposed to apply for by the way) is impossible. Their policy is well laid out, on the basis of your first internship's feedback, you get a second internship which you have to apply for by writing to HR well in advance. This is an assessment internship where you would have the opportunity to present to senior members of the team & basis that & your work you would be offered an interview & subsequently a PPO. Hope this helps.

Rarely and only as an exception. Usually it takes a couple of internships, but your first one will be the most important in terms of making an impression. If it is offline, then you stand a better chance. When you are nearing the end of the first internship, you may also informally ask for feedback from all the members of your team. It usually helps.