yeah, that merry/serious thread is really good... I think the basic delineation comes down to something like:

Fi/Te: If x is a certain type of person, they will act in certain ways.

vs.

Ti/Fe: If x acts in certain ways, they are a certain type of person.

Essentially, as you mentioned Jake, Fi establishes individual-specific assessments that don't exist outside of the subjective frame of reference, and Te serves as tensor-like beacons for these internal states (think of an internal reverberation in the human body which induces the entire muscular-skeletal chain to react in a directly observable way... that's Fi/Te in a nutshell)... it's hard to alter them, because it would require shifting the Fi'er's entire frame of reference. Conversely, Fe/Ti'ers assess people more inductively... observing the variations in latent activity and generating structural parameters to subsume the patterns underneath... and it's more detached, a bit more about interpersonal leverage than core maintenance (back to the human body metaphor, it would be more like isolating specific movements as observable entities, and "intuiting" the latent energy behind them, then comparing and categorizing said thing based on its more general relation to the other latent patterns observed, hence you have an interconnected chain of variant actions that find coherence on fundamental rules, i.e. the basics of the human body's functioning).