Congrats to all of you!!!
We go often, and all of your ideas sound great! For the OP, where are you staying? We love Ohana, as well as Cape May at the Beach Club. If you're heading to the Boardwalk, there are a few ice cream shops there, the sweets shop on the BW or there and Beaches & Cream in the Beach Club. There is a little lounge in the Beach Club called Martha's Vineyard that is usually pretty quiet. We like to go there by ourselves and have a drink or two at the bar. It's quiet and out of the way

We also really like hibachi, so we always make a stop at Teppan Edo in Epcot/Japan.
Narcoosee's at the GF is also really nice for dinner if you are seafood eaters!
I would definitely recommend a spa day! There is a Mandara Spa at the WDW Dolphin (buses go here as well as boats from HS and Epcot) that has a lot of awesome Couples Treatments. There is also a pretty extensive spa at Saratoga Springs. Endulge a little!
You could also take an illuminations cruise from the BW area- I think the boats actually leave from the YC marina, they take you right into Epcot to watch from the boat, or you can do the same at the MK resorts for Wishes.
Aaaaand you can go to the Tomorrowland Terrace Dessert Party in the MK- you have to make reservations for this and pre-pay. We have been probably 50 times and are going for the first time in a few weeks. Most people don't know about it! I think June reservations should be opening up any day now if they havent yet! TIP- if it says there is no avail. for a party of 2, change it to 3 (2 adults and a child under 3 since children under 3 are free).
Have fun!