As far as the cruises go, you must pay for at least one person (adult) per cabin with points. You may pay a cash price for the others in that same cabin if you so choose. The cash price is one that MS negotiated with the DCL and has nothing to do with points.
If you do not have enough points for your stay at a DVC resort, you can make a cash reservation with CRO for the additional nights. You cannot pay a combination of points and cash for the same night. You can also make a cash reservation for a 25% discount with MS if there is availability.
HTH. Post again if the above didn't anser your question.