Maybe somebody with inside knowledge concerning the logistics of how the cruise industry plans itineraries can chime in.
I guess I assumed when an itinerary is offered there is some communication between the cruise line and the port to confirm dates and berth availability. Having said that, I would think this would not currently be possible with Russian ports. I would assume communicating with the port authorities would be a violation of of the sanctions. I'd like to hear from anyone that might have first hand knowledge.
Also, besides for a Stockholm overnight, I'd love to visit ports in Latvia and Lithuania. Also some additional ports in Sweden and Denmark (just not on the Island Princess as is being offered this year 😉).
Finally, I'm pretty sure a vast majority of Cruise Critic users know you need to register your kids in advance. 😁