We have been to WDW the past two years for free dining. Both times my husband was there for only part of the trip. He arrived about four days after we arrived. He was required to be on the same itinerary as us, so his ticket and dining credits were the same as ours. The first year he only used two park days, so we upgraded his ticket to 10 days non-expiring and even added water parks. He used the non-expiring ticket again the next year and we just saved his unused ticket for a future trip. We did benefit by receiving all his dining credits, but we actually had some left over. The first year I called before I left because I was worried about it, and all the CMs said that he had to be on the same itinerary, if we ended up with extra credits, then enjoy an extra meal. I didn't even bother to call the second year. My husband also was able to use Magical Express 4 days later than he was scheduled to use it.
We had no problem checking in without him. However, the room was in my name. If it is in your husband's name, it could be a problem. No matter what you decide to do, if there is a chance your husband can't go, I'd put the reservation in your name.
We stayed at POP the first year and POR the second year.
If you think he may be there, include him in all of your dining reservations. It's much easier to show up with one less, than it is to add one more.
About changing your reservation: You can make any changes until your final payment (45 days out) without penalty. Within 45 days and 6 days, you will be charged a change fee. However, in my experience they don't charge it if you are upgrading your package (ie spending more money). That being said if you drop him before 45 days and add him back before 6 days, you probably wouldn't be charged extra. But I would confirm that with reservations.
