For dining only purposes, you could just use one account; but again, for FP purposes, it'll be much better to have separate accounts for each person, so it's better to go ahead and set them up now so that everything is streamlined from the start. You will need resort reservation numbers to do the 180+10 thing on your ADR's... otherwise, you could technically do them without those numbers, but you would only be able to do one day at a time, and then the next day you could do day two of your trip, and then the next day do day 3, etc. So yeah, it's better to go ahead and set everything up.