This was our second cruise with Celebrity (the first was New Zealand and Australia). The idea of this cruise was introduce wife and kids (Girl 13, Boy 15) to Asia while retaining the comfort of the cruise ship. Object was achieved and some lessons learnt along the way.
We had connecting rooms but could have had a family room without much impact.
Nice cabin which connected with 8143. Worked well for us. The kids had a twin and we had a double. The balcony weren't able to be connected on the Millennium like we could on the Solstice. Rooms were slightly bigger on the Millennium.
Hong Kong is an amazing city. Do it by yourself and enjoy the local experience. You need local currency but can by easily with English widely spoken.
Get to the beach
We just got a car to drive us around. Sanctuary of Truth is a must see.
Taxi services are great in Singapore. Take local currency for the taxis. Marina Bay Sands, Gardens by the Bay, Orchard Road, Boat Quay, Sentosa, the Zoo. So much to do.