Hi Diana,
Welcome back to planDisney! It's nice to see you stopping by again with another great question.
This is such a wonderful gift idea! There are a few options, so let's consider them. First, you could purchase
Memory Maker for the happy couple. With Memory Maker (Advance Purchase), they will get access to digital downloads of their photos taken with
Disney PhotoPass Service photographers. Or, you could purchase a
Capture Your Moment: Magic Kingdom Park photo session. This is a single photo session. My family did one. The photographer was fantastic, the photos adorable, and, the best part was the fun we had in the process. With either the Memory Maker or the Capture Your Moment options, you will need to link those to your cousin's MyDisney account, prior to the trip.
Another option would be to gift them
Disney gift cards. They could use the gift cards for other purchases, however and it sounds like you really want to gift them a photo package. I love the photo package idea - the memories will be priceless. And, they may want to use one of the photos from the Capture Your Moment photo session with one of their wedding announcement messages. We used one of our photos from our session for a winter holiday card.
Diana, as your cousin makes plans, be sure to take a look at the
Enchanting Extras Collection. There may be another special experience they might enjoy. In the meantime, your fairy godmother has taken note. The pixie dust has been sprinkled. I trust they will have a most magical time!
Magic and memories,
Donyell