Boreal Wanderers

Notes:

Hunters (Stalkers): Smarts and wisdom
Hunters (Chasers): Speed and agility
Hunters (Finishers): Strength
Herbalists: Tala's quest says smarts and wisdom, although it seems herbalist proficiency and level seems to be more important
Pupsitters: Nothing in particular
Scouts: Nothing in particular, though you need 101 strength to scout the rainforest and 101 wisdom to scout the glacier (both until fully unlocked, then any level wisdom/strength)
Mentors: Nothing in particular, though having higher stats helps to make sure they can be 1.5 times higher than the stat of the pup(s) they're training. They also have to have at least 5 levels.