Replacing peasants with wolves.

Well, there's no normal way to do it.
As I understand it, this is related to the IDs of creatures, and in principle, you can try this: replace the peasants in the first-level dwelling file of the Haven faction with neutral creatures such as wolves, mummies, or black knights; then, transform these three neutral units into new wolves, which is what you want to use to replace the peasants.
This way, the wolves recruited in the human city at the first tier will have different IDs, which means they won't participate in the chain of units trained by the "Counterstrike" skill.
As a result, there will be fewer interesting units in the neutral faction, and three versions of peasants will be added (they can, of course, also be redesigned to match the units that were the donors of the new IDs, but in this case, the next problem will likely arise: if the player obtains these neutral units with the IDs of peasants, they will be able to take them to the human city and turn them into archers - that is, the possibility of turning non-human units into archers will be preserved, but in this case, it will be possible, but extremely rare).
In general, it's better to cooperate with NCF and use those IDs specifically for the wolves.

Added 3 minutes later
Or even better, do this: replace human units with human units, and beast units with beast units (that is, so that the training chain always includes only humanoid units, and if wolves are really needed, let them replace griffins)