I think there is a good fit between TSM and NLP. Much of what NLP says about how we communicate with ourselves and other people is mirrored throughout the Seth material. As a matter of fact, a good Sethian could use NLP constructively to deepen their understanding of the contents of their own consciousness. I'm thinking here about how the different modalities and sub-modalities of NLP could be utilized more effectively in creative visualization.
I also like the way Grinder and Bandler explained 'parts', like Id/Ego/Superego, etc. It did a lot to illuminate my own understanding of intellectual constructs like Self, Soul, Personality, Ego, Higher/Lower self, etc. Many people like to categorize their intentions by assigning them to parts, a habit I find curious, though it is, of course, quite common. Personally, I refuse to have anything to do with a 'Higher Self', since I consider that cheating.
Ultimately, any kind of organizational principle, whether it's a Higher/Lower dichotomy or a Self/Other dichotomy is only useful as a stepping stone. I can't serve others without serving myself, and I can't serve myself without serving others in some way; similarly, there is no meaningful way to differentiate between my Higher and Lower self without arbitrarily assigning certain actions ('selfish' ones) to my ego and others ('noble' ones) to my higher self. These divisions are simply not useful to me. What is useful to me is understanding how my conscious thoughts directly shape my expectations and experiences.
Incidentally, you can learn a lot by hanging around in the hypnosis forums as well. Many professional hypnotherapists corroborate both Seth and NLP via their own therapeutic work even though many of them would not touch either with a ten foot pole.