She is a silver dapple, also called silver black.
She is very pretty. We have two yearling fillies that are silver black but they are closer to the cor of the Rocky Mountain Horse. Chocolate with lighter main and tail. One has a few dapples the other has none.
As for the coat shedding, have you wormed her recently. If not, she may need wormed.
Horses shed differently. We have had temps in the 90's for several months. We have one broodmare and a yearling that have a thicker coat than the rest. Everyone else is slicked out. Those two end of wet with sweat because of their thicker coats.