I thought I replyed to this post. Maybe it was removed, then again maybe it was when my computer crashed. anyways my thoughts on your question.
To me unrestricted means you can use the figure anyway you choose, commercial or privately or even educational, whatever.
I once created a female child obj without genitals. Oboviously it didn't need any, or did it? I exchanged the use of the obj for the use of a figure I wanted. The next time I saw that child it had genitals and was being used for [censored]. Not what I intended. I never gave the rights to alter the figure. And I see nothing on here that gives that right.
Some countries have laws agains copywrite infringement. I don't know what your country does. Even to take a piece of a figure and use it when it says not to be redistributed without permission violates the trust that creater gives in allowing you usage.
Lets say you took that knob, then gave credit. Now someone else takes that knob and something else from your freebe. Then someone else does it. Will the credit still begiven to the creator? Sounds far fetched? It happens and will happen again and again. If I take the legs from one figure and put it on another, then the arms from a third. That's not my work. I have no right to give it away even though they were free and I disasembled then reassembled.
I don't know how other's feel, as this is only my 2 fen worth.