Do you have an overnight stop in SPB? If so, I wouldn't book any excursion through
DCL in SPB. None of those spans two days. Some of the private operators have exclusive access to an inside tour on a day a museum is closed - such as Mondays for the Hermitage.
Secondly, if you can, get a private tour. This is what we intend to do the next time. A group tour follows a strict itinerary, and you can't change any of it. Well, isn't that how it is elsewhere too - you might ask? Yes, but the problem is, unless you have your own independent Russian visa, the guide/operator must accompany you wherever you go. So, you won't have your own free time - or start late, or end early, etc.
Copenhagen's hotel situation is a bit like Reykjavik's (in Iceland). For international tourists, it's a seasonal destination. It means the big brands hesitate putting a lot of properties that they know will have miserable occupancy outside of the summer season. Expect to pay through your nose in the summer when tons of cruise ship passengers must stay a night or two before/after.
Book early as the rooms will sell out. We experienced it firsthand last summer.
My recommendations:
* Steelhouse Copenhagen: Luxury "hostel" that your kids will love! We stayed there the night before our Baltic cruise last summer.
https://www.steelhousecopenhagen.com/
* Marriott: Must get two rooms for a larger family (such as ours), and it sold out last summer.
* Radisson Royal and Radisson Blu: The "Royal" is right across from Tivoli Gardens, while the "Blu" has family rooms. The Royal also sold out last summer.
* AC Hotel Bella Sky: A new Marriott property. This is where we are booked for next summer (before DCL's Iceland cruise). Will let you know how it goes, but it looks good.