The bad ending: On his way out, Thomas passes a twisted piece of metal hanging from a hook. It is his soul, which has been removed from him, and it is eternally screaming.
The good ending: And so Thomas reached immortality, his old parts melted down to make his new parts, and in time he came to rule his island nation.
Given that the waking candlestick can bend without fatiguing the metal of his form to the point of breaking, it's safe to say there is an active component to the magic that is sustaining their forms.
Given that the feather duster maid was seen to have her feathers forcibly removed, we can also assume they can be damaged and have parts removed.
The question is if they retain their soul, the abstract idea of who they are, in the individual parts of their body or in the collection of the whole.
Depending on the answer, he would either transfer his soul to the new part and assimilate it, fail to integrate the foreign and non-magical part, or grow a replacement part and force the foreign object out of his body.
"And that guy who's made of all my broken parts is a real asshole."