Maybe i'm late to the party, but i just discovered that settlers will equip the dog collar and chain dog collar like a wristband. Unfortunately not the others like the spiked collar. They do take up the entire right arm slot though. Wiki says that the SS can wear them too but it's known to bug out, so of course, no go on my toon. Anyone got this to work on theirs? Now if only i could make settlers wear bandanas on their head instead of their faces.

I just tried and I can't equip these... but it seems Piper can but she unequips her other clothes which is odd.