Hi Kathy,
Sounds like you've got an awesome evening planned! The Pirates & Pals Fireworks Voyage begins 1 hr & 15 min prior to the start of the fireworks. I checked the online calendar for MK for 11-15-10 & Wishes is scheduled for 8 p.m. That means P&Ps will start at 6:45 p.m. They recommend you get there 15 min b/f to get checked in.
Chef Mickey's is a buffet w/ lots of yummy food & b/c it is a buffet, the food is ready as soon as you're seated at your table. If your family are big eaters they may want to make several trips to the buffet which could take more time. You'll also want to make sure you have enough time with the characters - its an incredible character dining experience.
The 1st part of P&P's is also in the Contemporary so you can make it there in just a few minutes after your meal. If you aren't there right at 6:30 p.m. to check in, it won't be the end of the world.
I would see if you can get a reservation at CM's a little earlier or even arriving a few minutes earlier to see if you can possibly get seated earlier (sometime this works out - sometimes it doesn't). If you can't, don't completely stress out - just be sure you keep track of time. Even though P&Ps starts at 6:45 p.m. you'll be okay if you're not there right at that time but get there as soon as you can to enjoy as much of the land portion as possible. You will have just had a big meal so having time to eat the grab & go snacks at P&Ps won't be as important to you - you can grab some to eat later. You will want to be there in time to put on your pirate bandana & have your picture taken w/ Captain Hook & Mr. Smee before Patch the Pirate ships you out to sea.
You're in for a fabulous evening filled with great food, fun, laughter on land & the high seas. Wishing you many magical memories :-) Allison