Do you have access to purchase your military tickets from the MWR near a military installation? We have made a room only reservation with dining plan but no tickets using military discount. We bought tickets from MWR and linked them to the reservation so we could make fastpass + choices ahead of time. Either way you should be able to get magic bands with just room only reservation. I logged into the "my disney experience" account and picked what we would want not having a all inclusive reservation.
You and your spouse can each buy a specific amount of the discounted tickets. I would do the math and figure out if it is cheaper to purchase 3 days extra from WDW or if it would be cheaper to purchase 2 of the 4 day passes for each of the family members.