Note that one does not need Fi or Ti in order to use Fe or Te. Fe people can "learn the system," Te people can learn "how things are accomplished." It is simply that Fe or Te unguided by the internal sense of definition can sometimes run far astray, implementing and doing things that are inappropriate or that do not make sense.
(Meanwhile, the inner functions often remain unmanifested without the external functions to express themselves through.)
Ne to me seems based on the external input stream. With Ne, I look at something in real life, and I see all the possibilities realistically inherent in it. It has a connection to the tangible.I usually talk about theory, but I've heard Ni works differently from Ne. Ni is following one perspective/possibility, and then switching to another. Ne is being aware of all the possibilities inherent in the given situation at one time, with somewhat less awareness of where those possibilities lead, as far as I know. Basically, people with Ne have the ability to perceive several ideas at once, but with less depth. Is that how it works for you, or is it different than I've heard?
Ni seems more more abstract to me. rather than seeing the possibilities inherent in the world, I see all the possibilities in how I can reorient myself to the data stream.
So Ne is more about seeing the possibilities of external reality, while Ni is about shifting my own perspective/orientation inside and seeing the world in a different way.