I may not be understanding your question correctly, but your wife wouldn't be able to give her Magic Band to your son for BOTH of them to use for the same ride at the same time. They both have to have a band to scan in at the fastpass line entrance, and you can't schedule 2 fastpasses for the same ride at the same time on one band anyway. Fastpass+ only lets you schedule each attraction once, in your initial 3 choices per day.
You can definitely switch out bands. But you can't use one band to get 3 of you on a single ride at the same time, whether you are using rider swap or not. They aren't going to let 3 of you through the fastpass line with only one fastpass... unless rider swap is MUCH more lenient with rules than I'm remembering. Also, there is no such thing as a "freebie fastpass" because you have a child who's 5. They will expect him to have a fastpass just like both adults with him. Sure, he can re-ride with rider swap on a single fastpass, but unless I'm misunderstanding - you're hoping that your wife's one fastpass will be fine for both you and her. The only people who don't have to have fastpasses are the babies and toddlers, who aren't old enough to have their own accounts set up to schedule fastpasses and are expected to only go on rides where they are lap babies.
It doesn't really matter if there are two adults, or if there is one adult with a 5yo - they are both supposed to have a fastpass on their magic bands to get on the ride via fastpass. Like I said, the only people who aren't required to have fastpasses are lap babies, because you can't set up fastpasses for them at all. Lap babies do not affect ride load b/c they aren't taking up their own seat.
I just have to tell the OP that we seriously disliked the breakfast at Ohana. Mass cooked scrambled eggs and nothing else that was especially tasty or out of the ordinary. Unless someone in your family is a huge Stitch fan, I'd book anywhere else. (Dinner at Ohana is another story. We love it!)
My personal favorite for breakfast is 1900 Park Fare at the Grand Floridian. But you should consider the Cape May Cafe for breakfast since you're right there, and they have a make-your-own-crepes station. For that matter, we really like the dinner there, but if your wife hates seafood, it may not be your best bet.
Regarding transportation, I would use my car for going everywhere while you're at Pop except the Magic Kingdom. You have to drive to the MK lot, take a tram to the TTC (Ticket & Transportation Center) then take the monorail or ferry to the MK gate. Pop's bus will let you off at the gate.
The same advice for the MK applies after you move to the Beach Club, but you should also use the boat for Epcot and the Studios.
Hope your first trip is magical for you and your family!
Where is sleepy hallow? My daughter would die for a nutella waffle!
