Just this week I cancelled a room-only reservation to book a package instead. I had read horror stories about people losing their ADRs when they did the exact thing. The CM transferred me to Dining so I could have them link the ADRs to my new pkg. reservation.
When the Dining CM answered, she said that ADRs are never automatically cancelled when a resort reservation is cancelled. They have to go in and manually cancel them. She didn't even want my new reservation number. She did pull up all my ADRs and confirmed that they were all just as I thought they were.
I've checked them only since then - just in case she was wrong, but they are still there.
So, I think they will not be cancelled, but it sure doesn't hurt to ask them to make sure. Good luck!