I believe you have to take the fx layer it gives you and put it in your avatar's 'Base' slot, but I could be wrong since I don't usually edit the locomotion.
If you don't know where this option is simply click on your entire avatar and look to the right side under "Playable Layers" there should be a section that says "Base". There will likely be an fx layer already called "(Avatar Name)_Locomotion", just swap it out for the new fx
Again I hope this works as I am not a million percent confident
Manuka does have a head bone, you must open the armature and drop down the Hips, Spine, Chest, Neck, and then you will find the head. Then just place the hair on that bone.
Drag and drop the hair prefab onto your avatar in the hierarchy, go to the hair and select the hair armature and drag that onto the avatar's head armature.
R
