A) ONLY a comm officer with the hacking upgrade (Communications I B) will be able to do this, and they will have to be very creative to get it to work properly. It's possible, it will just be very difficult to pull off and to maintain a connection! (But there's nothing stopping you from hacking in again, and again, and again, of course~)

B) They can make that happen, certainly! It will be the same stun effect as previous.

C) As long as they can maintain the connection and the girls continue to sing, the Vieziri will be stunned. However, the longer it goes on, the more the Vieziri will attempt to struggle through the stun/sluggishness regardless - so the effectiveness might diminish over time, though not by much.

Let us know if that needs any clarification!