Now I have vertigo. Others may know better on the cash but my understanding is the 7/11 month windows do not apply other than you must be inside the 11 month window for them to even have the days. Remember these cash rooms come from several different sources so the availability may vary over time. You cannot convert the cash rooms to points but you can make a points reservation for the same thing if it's available and cancel the cash reservation. I don't know if you can cancel day by day, esp for a day in the middle of the cash reservation, maybe someone else knows more. The cash prices will be based on the rack rates which are significantly different seasons than the
DVC seasons. The only question is whether it's rack rate or 25% off. Sometimes CRO is cheaper but you can't formally link CRO cash reservations to a DVC reservation.
Sometimes cash reservations are a better deal and other times it's better to use points. Variables are how the DVC seasons stack up to Disney hotel seasons, weekend vs weekday and whether you can get the discount or not.