Followers will only gain benefits from the following enchantment effects on their apparel and armor:
Fortify Health
Fortify Health Regeneration—only works during recovery phase/out of combat
Fortify Heavy Armor
Fortify Light Armor
Fortify Magicka
Fortify Stamina
Fortify Unarmed Damage
Muffle
Resist Fire
Resist Frost
Resist Magic
Resist Poison
Resist Shock
Waterbreathing (Followers won't drown anyway, but this stops them surfacing for air.)