We are splitting our stay and doing the
DDP for 4 days and no DDP for 4 days. When I called to make my ADR's, I couldn't get 'Ohana any time during my DDP days, and I asked her to try and book me an ADR where we paid out of pocket instead of using the dining plan. The CM said it didn't matter - on or off plan was not a factor in booking the ADR.
I had thought they had set aside a certain number of tables for DP people so I was surprised to hear this.
Some ADR's require a credit card hold. If they don't ask for this, then you can cancel without penalty. And even if you do book something like CRT with a credit card, I think you can cancel up to 48 hours in advance before you would get charged.