Yes you do kill the real Emperor or at least his original body but as we have seen from Palpantine powerful Sith can leave there bodies and control others so it is possible that his force spirit took control of one of his children who were attuned to being controlled by his force spirit anyways.
No you do not. The Emperor's real body is a Sith Pureblood. In the JK story line he is a human. He's still alive, just probably really weak. Also when Kira talks about how her friend can hear the Emperor still, it's just his weakened and fractured mind reaching out to the galaxy. His presence must be so weak that the Dread Masters don't even feel him in the force. Also, if that was his original body, why would he bring it into known space? If he is as clever as he is, he would use his voice to do the ritual so that if he fails, he will have a body to fall back to. Also, his Hand stated that in fact he is still alive only weakened and in Unknown Space. Look on all possiblities before using radical theories please.