Hi Jeffrey,
Once the DR receives the register stop, it will start a 60 second “register suppression” timer. During this time, it will not forward any PIM register messages to the RP. Five seconds before the timer expires, it will send a “null register” message to the RP. Now there are two options:
Option 1) The RP still doesn’t have anyone that is interested in the multicast stream, if so it will send another register stop message and the DR will reset its suppression time.
Option 2) If the RP does have receivers, it won’t send anything to the DR. The DR its time will expire and it will send another PIM register message with an encapsulated packet.
About your second question, I believe the packet will be forwarded to the receiver but I’m not entirely sure how this process works…I’d have to lab and debug that to take a closer look 
Rene