Maybe skills are like the proficiency come up with a working plan (Te), proficiency to in hand-eye coordination (Se); And preference is the psychological drive to come up with a working plan (Te), psychological drive to participate in activities requiring hand-eye coordination (Se)?
I can't really think of any examples for Te or Se, but I can for Ne in an INTP. I don't know if it's really how things go though, I'm still not an expert, and most likely never will, in functions.
Say for example an INTP who loves using Ne (psychological driving force) but isn't all that good in doing so (lack of 'skill', thus drawing less connections to make sense of things as he/she would have liked to) and has to think of a solution to a problem. He/she uses Ti supported by Ne, draws very little connections and ends up being unable to solve the problem or giving S-like solutions as there might be a chance of him/her having to resort to using Si or Se to fill up the gaps. Is it improbable, but possible for Si/Se to be ingrained into the psychological driving force instead of Ne through long periods of usage? Like using it so much that it becomes second nature, preferring Si/Se to Ne automatically without conscious thought?
Well... Ragingkatsuki and Simulatedworld explained it better than me in these posts regarding INTPs who does not use Ne as much (though they did not talk about whether it was by preference or learned).
(Does that mean my questions in the first post are still valid? )