Hi Daniel,
It sounds like you are planning a fabulous honeymoon!
Mickey's Not-So-Scary Halloween Party is a wonderful event. It is absolutely the time for adults to dress up. Last year, my family went the the party as a family of fairies - with myself and my husband wearing grown-up sized sparkly fairy wings! We got great comments on our costumes all night long. Although not all of the attractions will be open during the party, many of the most popular ones will be, and the lines tend to be shorter since there will be less people in the Magic Kingdom than on a typical day. Also, the entertainment that is exclusive to this party is fantastic. Mickey's "Boo-to-You" Halloween Parade is great, including gravediggers dancing with shovels. The Happy HalloWishes fireworks spectacular is not to be missed. Please do note that entertainment may change from year to year. If you are ready to have some fun and channel your inner child, which I think that you are based on asking this question, you should go for it and have a great time at Mickey's Not-So-Scary Halloween Party.
Also, I suggest that you keep an eye on the
Epcot International Food and Wine Festival for 2014. This event typically starts at the end of September, and includes the opportunity to purchase and sample great bites of food around World Showcase, as well as some really unique special events, such as special dinners and parties. Attending one of these may also be a great special night for your honeymoon.
I hope that this helps give you some ideas for planning your honeymoon, Daniel! Have a great time planning, and please do not hesitate to ask if you have any further questions.