It is a resort, so no breakfast for Golds (or Plats). There's also a resort fee, and parking is extra as well (NOT included in the resort fee).

The Wailea Marriott is a quick walk to the Shops at Wailea (just across the parking lot):
http://theshopsatwailea.com/

There are some shops and restaurants there, but it's a relatively small shopping center. But with a car, you leave when you want something different. You can also try some of the other restaurants at the other resorts in Wailea (some have a nice view) -- all are within walking distance, though with a baby, it may be a long walk to some of them.

I believe there's a separate pool for families, though I haven't used it myself. The nicest pool at the resort IMO is adults-only -- it's an infinity pool with views of the ocean.