Bonjour, Laurel! I am so happy that you got dinner reservations for Be Our Guest. It is one of the most beautiful dining locations in all of Walt Disney World, in my opinion. There are three impeccably themed dining rooms including the West Wing and the Ballroom. Be sure to take in all of the details of the rooms like the cursed rose, the lightly falling snow outside of the ballroom, and the talking suits of armor. Music from the film ties it all together and makes the aesthetic experience one you'll never forget.
A dinner here is never second best! I can vouch for the Braised Pork and Master's Cupcake. Not only are they are absolutely delicious, but it also magically finds its way to your table in a beautiful glass domed cart.
You did not mention what day of the week that you would be visiting. Whether or not you'll be able to enjoy Wishes nighttime spectacular and make it to your dinner reservation in time is going to be dependent on the day of the week and what season that you are at The Magic Kingdom.
The Wishes nighttime spectacular has been known to start anywhere in the time frame of 8:00 p.m. to 10:00 p.m. I suggest that you follow the link that I provided above and check out the hours on the right-hand side of the page. You will see a small calendar icon. Click it and choose the date that your reservations fall on. Since the page notes the duration as approximately 12 minutes, I would say that you could catch the show if it had a starting time of 8:00 p.m. or 10:00 p.m. Just find a good spot close to New Fantasyland so that once the show is over you don't have to fight the crowds to get to your reservation.
And now we invite you to relax, let us pull up a chair as the dining room proudly presents your dinner!
I hope this helps, Laurel, and if you need anything else, please be our guest!