Hi there,
Zaks on the waterfront very near to the ferry pier is child friendly with a little play area, also has very good food and the service has recently improved a lot.
Then you will probably head to the beach for the afternoon, or when you get there although it may be a little busy. There is a childrens play ground at the far end of the beach.
The centre, the plaza will also be full of families and there is likely to be some event happening family orientated, although I don't know what, in the plaza too.
Hope this helps.