I've stayed at the W and the Four Points. The W is definitely in a dramatic location and a beautiful hotel, but you will have a walk to any transit other than the tram across the water.
The Four Points is close to transit, but a long walk to most of the tourist sites. It will have the advantage of shopping near by for the times you stay in or need things for your child, but it is definitely a work, not a play hotel.
I haven't stayed at Le Meridien, but I can definitely vouch for the centralness of the location. Given what you've mentioned, that would be my first choice.