Have you looked into My Family Time dining? Seating at 5:30 (at least on our sailing).
Are you asking *if* Sorrentos and Cafe Promenade are fee or no fee? Or just opinions either way?
DS's favorite thing on the ship was all the chocolate Ben&Jerrys ice cream he had. The more we went the more the employee got to know him/us, and the more generous the guy got. Towards the end of the cruise DS ordered a chocolate milkshake, and the employee put SIX scoops of ice cream in it.

DS loved the guy.
We liked our espresso drinks from what I consider to be Cafe Promenade (but I think officially it's called Lattetudes). Again, the more we ordered from them, the more they got to know us.
The few goodies we got from Cafe P were OK, but not spectacular. I think the lemon poppyseed muffin was the best.
DS had Sorrentos pizza a couple times. He was back and forth on it.
Stores...nothing really special there in our opinions. They had some souvenir shirts and I was able to buy a big floppy sunhat when I just didn't want to wear my running cap. They had little christmas tree ornaments of the ship. Oh and if someone wants a pretty, blingy, lanyard for their SeaPass card, they had them for 9.99. And they'll punch a hole in your card perfectly over at Guest Services.
Speaking of lanyards, Adventure Ocean has them too, and they will also punch a hole in the card for the kids so the card can go on the lanyard. Not sure if the 3 year old will get that, but the 7 year old, definitely.
I think we avoided the SailAway party. Not sure why. It wasn't really our "thing" on
DCL, and we decided it probably wouldn't be on RCCL either. And I think we were exploring.
We got the Replenish package, and we didn't take advantage of it enough. Didn't even break even. We drank espresso drinks, had bottled waters, and DH had some fresh-squeezed OJs in the morning. We forgot about the sparkling water and didn't realize the ingredients in the virgin frozen drinks were OK for DH so missed those, too.
If your family drinks soda, the plain old soda package is pretty much a no-brainer. You get a cup (you get it with the Replenish package too, and it's now my water cup...it actually keeps water just as cool, if not cooler, as my DCL Tervis cup does) and the Freestyle machines are...let's see I saw one right near Sorrento's, and then there's also one in the arcade. And the arcade is what you have to go through to get the 7 year old from his kid club. Noisy noisy. And tempting.
OH, if you guys like arcade games, be sure to check the Compass to see if there's a Free Family Arcade! On our sailing it was Day 1 from 7-8. All of the classic games were FREE for that hour. Not the big machines, and not the machines that give tickets (for prizes that you get from another machine), but Donkey Kong, Pac Man, etc. Fun. And free. But of course then it just whets the appetite of the videogame lovers in the household.... (it's like they know what they're doing, LOL)