recommendations on suburbs for families and dog

moving from Auckland with 3 young children (into sports) and a dog whom I enjoy taking for daily walks on the beach and in parks. Would like recommendations on areas very close to the beach (particularly dog beaches) and within 30 minutes of city centre and on a train line through the suburb. Obviously good schools. Just looking at the map, I fancy cottesloe, Mosman park, North fremantle, north beach, city beach and even Hilary's boat harbour area looks quite nice (but do the trains go that far up?) Would love a nice outdoors lifestyle and go sit at a cafe with the dog after a dog walk on the beach. Don't want to live in a suburb with not much amenities though. Any recommendations and also how do these areas compare expense wise. Thank you in advance.