Thank you Ambatman for the clarification.  It makes sense that the binary string of bits would be supplied to the PBKDF2 function.

I appreciate everyone's help on this!

I believe I am now good to go.  I did not realize how much happened to the 128/256 bits of entropy before arriving at the ACTUAL PRIVATE KEY.  Pretty crazy!  But obviously anyone in possession of the seed phrase or entropy that it represents might as well be in possession of your Private Key.  That point has been hammered home.  I guess that is why I always thought the 128/256 bits of entropy that the mnemonic seed phrase represented WAS the Private Key.  Go figure.

Thanks again everyone!  You guys are awesome!

Kresp