We are a group of 5, adults and high schoolers, planning a trip to Scandinavia in June.
We arrive in Copenhagen and head back home from Stockholm.
We have 10 nights, 9 whole days after arrival and before the flight back home. This is set.
We want to do a fjord tour (possibly the nutshell) to sample a bit of the fantastic Norwegian landscape in between Copenhagen and Stockholm. So it will be 3 days at each City.
Copenhagen- 3 days, day 3 night ferry to Oslo (there’s an overnight (16hr) ferry from Copenhagen to Oslo. This would help us save some travel time.)
Oslo - 3 days with day 2 a round trip nutshell tour via voss.
Stockholm - 3 whole days. Train or flight from oslo.
Questions:
1.We want to see Kronborg. The ferry leaves at 5pm. Considering traffic and ferry check-in, do we have enough time during day 3 to visit Kronborg b4 catching the ferry? Or should we do this in day 2 at Copenhagen. Then what can we visit during day 3 before the ferry? We will do hop on and off bus or bike rides while in Copenhagen city center.
2.Where would we leave our luggage during day 3 while tour? Are there lockers at the ferry port? It’s a DFDS ferry. Or should we use train station lockers?
3.Any other suggestions on our routing from Copenhagen to Norway? Our main focus in Norway is to see the fjords. But we want to do a day trip, not spending overnight during the tour.
4.Should we give one more day to Copenhagen and stay 3 nights 2 days in Stockholm?

Thank you for your replies and suggestions!