Mallard, Mottled, American Black Ducks?

It is challenging to identify duck types. 

When I found duck eggs in the butterfly garden near the pond (cracked open as if hatched), I wondered whether it was a Mallard or Mottled duck nest. I needed ID help from the Facebook group, What's this bird? They thought that all were to some degree Mallard and that 3 in this photo were part Mottled Duck. Another felt that the duck furthest in the background was an American Black Duck. 

I linked each to All About Birds (Cornell Bird Lab) so you can look for yourself and take a guess about their ID.

Many species of waterfowl form hybrids, and Mallards are particularly known for this, hybridizing with American Black Duck, Mottled Duck, Gadwall, Northern Pintail, Cinnamon Teal, Green-winged Teal, and Canvasback, as well as Hawaiian Ducks, the Grey Duck of New Zealand, and the Pacific Black Duck of Australia. - All About Birds

The family hangs out in the garden and pond nearby. 

Here is a part of a hatched egg and a view of the setting. See the duck egg under the Muhly Grass?

Here they are nibbling away at the pond edge.

Mottled Ducks consume a variety of plant and animal matter, which varies greatly by region and season. Common plants taken include the seeds and shoots of many grasses, wild millet, smartweed, spikerush, paspalum, sea purslane, wigeon grass, and bulrush...Mottled Ducks meticulously strip grass and rice seeds by rapidly opening and closing the bill along the length of the seedhead. Invertebrate prey include snails, crayfish, beetles, amphipods (zooplankton), dragonflies, and midges. Small fish are also eaten. Breeding females consume mostly invertebrates, as do ducklings. - All About Birds, Mottled Duck

This (mostly) Mottled Duck was quacking. I read that quacks come from females and the raspy-type duck sounds are the males (All About Birds). 

The quintessential duck’s quack is the sound of the female mallard. Females often give this call in a series of 2–10 quacks that begin loudly and get softer. When courting, she may give a paired form of this quack. The male does not quack; instead he gives a quieter, rasping, one- or two-noted call. Ducklings make soft, shrill whistles when alarmed.

Here are two of them hanging out with a Great Egret who moments later caught a fish. 

After I took this photograph (they were across the pond), as quick as they appear to fall asleep, they woke.