All hexbloods show these traits, but the details differ
Van Richtens Guide to Ravenloft, p. 18 continues
Along with these marks, hexbloods manifest hag-like traits,
such as darkvision and a variety of magical methods
to beguile the senses and avoid the same.
All hexbloods have the Darkvision feature. As this feature is gained along with these marks, all hexbloods have these marks. Nothing in the text suggests it would only be one of the marks, or some if the marks, so "these marks" are all of the marks.
The text further says (emphasis added)
Every hexblood exhibits features suggestive of the hag whose magic inspires their powers. This includes an unusual crown, often called an eldercross or a witch's turn. This living, garland-like part of a hexblood's body extends from their temples and wraps behind the head, serving as a visible mark of the bargain between hag and hexblood, a debt owed, or a change to come.
So the details differ by hag type. For example a sea hag hexblood would have blueish skin, while a green hag hexblood would have -- you guessed it -- greenish skin. There even is a picture with three different kinds of hexbloods on the page, and they all have all the marks: the crown, long hair, pointed ears, and garish skin.