I have also rented with David's several times in the past and always had great experiences. As long as covid is a concern, however, which is a certainty in December 2020 I would say because we could be in a 2nd wave, I would NOT enter a non refundable contract. The other issue is that December is DVC's high time AND all DVC members affected by the closures are having to cram into the next months, so availability will be especially limited. Normally DVC reservations are spread out over 12 months, but now that the parks have been closed several months, everyone has to use those points in a shorter window before they expire. I think you will find that renting points might be hard to do for a while, especially in DVC high seasons. My advice is to book directly with Disney. It is the safest thing to do at this point and will be the easiest thing to cancel or reschedule should something happen.