I have two questions concerning WILD, the first is: Is it normal to experience audio hallucinations while attempting this method? And: Is it actually possible to re-enter a LD by drifting back to sleep and not breaking SP? If so, how long might it take? I have attempted this twice, only to give up and record my dreams lest I drift into a ND and forget what happened.
you may wish to correct the topic’s name…
first question: Yes.
second question: Yes, we call it DEILD.
third question (you said you only had two): from 10 seconds to 2 minutes, usually around 30 seconds.
The title for this topic is perfectly appropriate. Welcome to LD4all! 
My experience is that audio hallucinations are more common the closer I get to SP.
It is possible to re-enter dreams both from SP and after waking up more properly. You don’t have to give up if SP breaks. Personal experience may vary, some say that not moving is the important part. It has sometimes taken me several minutes under good conditions (no noise etc), but I don’t often wake up still in SP.