Natural Selection is not removable from the theory of evolution. Because of this, I have a difficult time answering yes or no to the synonymous question, because again, my hands are tied by the ropes of methodological materialism.

I don't understand the problem here. NS is not synonymous as a title, for a portion of a process, with the word for the total process, evolution. NS is just a portion of the process. NS is not syonymous with the word evolution.
I don't need to repeat the definition of 'synonym' here.