This mystery dog is extreme white spotted. So it immediately rules all solid breeds as one of the parents.

He also seems to have flying nun ears, which genetically suggests a mixing of parents with different ear sets. Eg., an up-earred parent, rose ears and one with flop ears or mixed breed parents - resulting in indeterminate ears carriage of the adult.

On ticking...
Ticking is genetically dominant but the manner in which spots are distributed is controlled genetically in a sort of 'plus' vs 'minus' way.

Belton colored (like English Setters) and intensely speckled German Short Hairs are ticked. Because these breeds are pintos you can see the speckles in white areas. Since the trait is dominant, only one parent needs carry it. Collies and Springer spaniels have ticks too, but breeders tend to select for white ruffs around the neck so the appearance is cleaner in most lines. But crossing with another breed can cause offspring to have different ticking traits. (Solid dogs can be ticked too, but since they have no white markings, the ticking is hidden)

The color black is dominant over brown or chocolate. So one parent could have been a chocolate breed that carries belton spotting - so don't rule out a parent that has traits similar to a GSP.

Since the mystery dog is short coated, which is dominant, then either parent could have been long coated.

When doing breed ID based on color and morphology of the dog, it is useful to understand color genetics in the dog. So this analysis rules out several breeds and introduces possible parents that haven't been mentioned yet.

Many mixed breeds are mixes of other mixes, and the genetic QTLs for behavior can be very unpredictable in mixed breeds. So just because one parent is a herding breed and other is a hunting breed, the puppy may have behaviors that clash in a confused way, or have no specialized traits from either parent.