Fork of your plunker: http://plnkr.co/edit/yeP4zfi79KFHTHzBLxK5
I changed things around a little bit, added the kids object to the moms array (converted this to array, it was easier). The tricky bit is getting the index into the inner function, like this:
for (var i=0; i < $scope.data.moms.length; i++) {
(function(index) {
Kids.get({'mom_name': $scope.data.moms[i].name}, function(response_two) {
}).$promise.then(
function kids_success(value) {
$scope.data.moms[index].kids = value;
},
function kids_error(error) {
$scope.data.status.push("kids service returned error="+error.data+error.status+error.statusText);
}
)
})(i);