Just showed our passports when we checked in at Dover and when we left the ship in Dover. We did have to have our passport to get back on the ship in one of the ports but I don't remember which one,
DCL gave us notes on our beds every night reminding us of things we needed to do.
Also in Russia we had to keep our passports with us and give Anastasia a copy of them plus a copy of the credit card that we were using to pay for the excursion.
Another thing that I found useful(a passenger told us) that if we only had a little of the currency left from the countries we visited to leave it for your stateroom host or dining servers. They can't exchange on board and DCL is trying to give them time during the 4 cruises to be able to get of the ship in some of the countries for a few hours. They can use the money for buses.
Kids clubs were not open as many hours as on previous cruises and seemed to have fewer planned activities. IMOP - We did NOT like to new rules for the floating ages in the clubs or the changes that have happened to the Lab as a result in these!