How To Swap Out A Characters Clothing?

So I have a skinned character, along with 3 pieces of skinned clothing (pants, jacket, and shirt). I would like the ability for a player to be able to add a piece of clothing to the character. Eventually I would like to have the player to be able to buy additional clothing, so I'm trying to figure out how to set it up.

Right now I have an FBX with the character and all the clothing together, so I can easily activate/deactivate each mesh renderer to show/hide each piece. That works, but I would rather have that clothing load/unload during run-time. I'm not sure how to set that up.

Originally I thought I can bring each piece of skinned clothing into Unity as a separate FBX, convert it to Humanoid, and assign the same Animation Controller as the character. But since the clothing uses less than 15 bones, I can't assign the Humanoid configuration.

What's another way to do this?

Thanks!