Hi Bryan!
You are planning on enjoying two of my favorite things in Magic Kingdom:
The Crystal Palace and
Mickey's Not-So-Scary Halloween Party! My family loves The Crystal Palace and it's one of our favorite Character Dining experiences at Walt Disney World Resort due to it's fun Character interactions and really tasty dining options. We also love to enjoy the tricks and treats of Mickey's Not-So-Scary Halloween Party. So both in one day sounds like a
practically perfect Disney day!
In order to enjoy your meal at Crystal Palace, you will need a valid theme park ticket to enter Magic Kingdom to get to the restaurant. You are correct that Mickey's Not-So-Scary Halloween Party tickets will allow you entry into the theme park at 4:00 p.m., but that is not early enough to accommodate your 2:30 p.m. reservation. So unfortunately, to accommodate both your dining reservation and the party, you would need both a standard theme park ticket for entry to the park early enough for your dining reservation and a Mickey's Not-So-Scary Halloween Party ticket to stay in the theme park after 7:00 p.m., when the party begins.
If you will only have your Mickey's Not-So-Scary Halloween Party ticket for that day, I would recommend that you enjoy lunch at
Chef Mickey's. Located at Disney's Contemporary Resort, you would be able to enjoy a late lunch with Mickey and his friends and then walk or take the monorail right over to Magic Kingdom to enter the theme park at 4:00 p.m. using your party ticket to enjoy Magic Kingdom before your 'not-so-scary' evening!
T-T-F-N, ta ta for now!
~Crystal