As a somewhat regular at Chungking Mansions, for a variety of reasons unrelated to accomodation, my heart dropped when you said you accidentally booked your family accomodation there for Christmas.
No point spending money on tickets to visit HK and then booking accommodation at Chungking for a family holiday unless:
1. You are not bothered by cockroaches, urine in hallways, 'hotels/motels/guesthouses' with 1 star or minus ratings, regular fights and a lively 'alternative night time economy'
2. You really can't afford anywhere else and will simply take the mayhem in stride, determined to have a good time anyway.
On the plus side, and yes there are plus sides to Chungking, you will:
1. Be centrally located by Kowloon standards (barring the protests)
2. Have a quick commute to Central and other parts of HK (barring the protests)
3. Be able to experience racial diversity in otherwise inconceivable ways in HK
4. Have a plethora of 'private kitchens' and 'restaurants' from every continent conceivable, some of which are actually highly rated, others are frankly a stomach virus waiting to happen.
5. No shortage of on-site money transfer options, bars, laundromats, barbers, hair salons and grocery stores
6. A welcoming committee of gentlemen who stalk the entrance offering all who enter, hourly and nightly rates for accommodation with cheeky smiles and raised eyebrows.
Go with grace and have a wonderful time in HK.
Despite our present challenges and the ridiculous cost of living, Hong Kong is still well worth a visit.
Just be an informed visitor.