I never reply to these kinds of posts, or write here very much at all. But its cute how you're worried about taking your family to the split...
Take your kids to the spit... they'll play in the shallow water, and use the bathroom, and everything will be alright. Lee's made good suggestions for lunch.
Its an easy walk from the tender's dock, to the water taxi. Just make a left. Keep an eye out for a guy with a giant snake around his neck. He's not a kook, he's a scientist, called Smits. Stop and talk with him.... he'll even let your kids hold the snake, if they want to. My grandparents' friends took their family on a cruise to Belize, and all the kids could talk about was Smits and his snakes (one little girl was enhtralled, and the other was terrified)
water taxi rates & schedule are at www.cayecaulkerwatertaxi.com
. If one of the kids is to small to handle the half mile walk to split, once you reach caye, you can get a ride for maybe $3.
If I see a family with three kids by the split in January, I'll say hi, in case its you.