It may be useful to be strategic about your seats. Recently flew J on CX on a A359 with wife and two young children (3.5 y/o & 18 months). We picked 3 seats on one-side of the rear mini-cabin and CX typically blocks the 4th seat until check-in due to proximity to the lavatory. Ultimately, we were able to use all four seats on two of the legs.
Completely understand this is a very specific situation, however it may be worth watching the seat maps for your itinerary.