Gifted Gourmet, I'm familiar with most of the restaurants reviewed on the Fodor's site, and can add a few comments:
Probably the most "kid-friendly" of the restaurants listed is Johnny Harris', and it's definitely a setting for a memorable meal: Octagonal dining room, live music and/or dancing on Saturday nights, and I've never had poor food or service there. From the Marriott, it's only about 2 miles via expressway, with plenty of parking. They're known primarily for their BBQ and steaks, but the seafood is typically fresh and well-prepared.
Elizabeth on 37th is (again, in my experience) always good, but I'm not sure whether I'd take my own 8-year-old there for dinner, lest he disturb others who are enjoying an "occasion" meal. Parking can be a problem, and it's not located in a neighborhood where I'd want to trek with small children.
Personally, I love both Georges' and the North Beach Grill (both owned by the Georges -- two guys named George, so the apostrophe isn't misplaced!) However, they're a pretty far piece from the Riverfront, out on Tybee Island... NBG is a total dive with great food, but not necessarily the spot for a celebratory meal with the family. Georges' is more formal, but tends to get pretty crowded: Two boys who have spent the day in the car might not enjoy being cooped up!
Most of the other restaurants listed by Fodor's aren't really known for their seafood. Bistro Savannah seems to be well-reviewed, but I've only eated brunches there (and heartily recommend!) Another spot, not listed by Fodor's, that might meet all of the travellers' requirements: The Aquastar at the Savannah Westin. From the Marriott, one can take a short walk down the waterfront and then take a water taxi ride across the river to the Westin. The views from the restaurant are amazing, and the restaurant has received glowing reviews from everyone I've spoken to.
For more restaurants and reviews, here's a link to the Savannah Morning News restaurant guide
, with linked reviews. Mind you, some of the reviews are out-of-date (restaurants closed since review.) Cucina offers the best advice, though: contact the concierge for the most up-to-date information on what's open/closed/requires reservations/etc.