Interested to see which wolves are covered: "as well as a cadre of Space Wolves and Salamanders who have appeared as major characters in previous Horus Heresy novels".
Howl of the Hearthworld doesn't really qualify as a major character in a novel.
Bodvar Bjarki and his watch pack from Crimson King seems like the most obvious choice, however it wouldn't really call them major characters.
To be honest im happy with any extra wolves in the siege series as i was only really expecting to see Russ and Corvus (as well as Ultramarines and Dark angels) in either book 10 "breaking the siege" of book 1 of a scouring series.