I am considering this very thing right noew. As per MS only the first adult passenger per cabin needs to use points if you want to use the point/cash option.
At this time, I am planning on using points for the adults and cash for the children as the discounted difference for cash only is not as big w/children.
A suggestion that was given to me by a
Disney cruise person (who is also a
DVC member) is to book and pay the $200 deposit per person at the early booking price(if it applies) w/
DCL and then wait to see if DVC offers any cruise specials prior to the time of the cruise and then decide if you want to cancel the res. w/
Disney Cruise Line, and get your deposit refunded, then book w/ DVC.
Of course this seems a bit complex, but at least their are options when you are a DVC member.
FYI-If using points, the $75 fee is per transaction, not per cabin. So if you book more than one cabin and pay cash for some of the passengers in each cabin, but use points for the first adult in each cabin, you only pay one fee.
The more I learn, the more confused I get!!!