WATERLOO — The mother of the two children who died in a Waterloo house fire early Thursday died Friday in Iowa City.Amber Dawn Everman, 33, died at University of Iowa Hospitals and Clinics in Iowa City, authorities said.Two of Everman’s children — Amari Burkett, 9, and Ava Everman, 6 — died in the fire at the family’s home at 1815 Commercial St., reported shortly after 4 a.m.