My family will be on the Celebrity, August 5th trip as well. I have three daughters (22,17 & 15) and one son (11). We picked Celebrity for the first time. We have done RCCL in the Caribbean a few times, once with kids. We have let the kids look through all the excursions and they are not into it as much as the Caribbean more fun activities but still into it. The kids are all excited about going to Europe for the first time. I like to stress the age of everything in Europe, Our oldest tourist sites are 400 yrs old. Things being built 1000 yrs ago is amazing. The movie Gladiator is good to watch for Rome and then seeing the Collusiem. The movie The Italian Job is set in Venice at the begining. I have recorded several shows on the travel channel anout Rome and Venice. They are excited about hiking a Volcano in Naples. I think that we all will be so tired each night from site seeing that after dinner and a show my kids will be headed to sleep(I know I will be). During sea days they will have plenty to do exploring the ship and swimming.
It's good to know they will have at least two kids their age on board. I am sure they will meet at some time.
Let me know if there are excursions that your boys seem to like.