I wrote this definition on Ni in a discussion in the wiki; Jonathan thought it was very good, so here it goes --
The early socionists, including Augusta herself and Stratiyevskaya, emphasized a lot (too much imo) the "intuition of time" aspect of Ni. I see Ni as the inclination to wander off into your own internal imaginary world, going deep into it and following it for a while, rather than jump between different ones "on the surface", which is more Ne. That imaginary world is often reflections on the past and on the future, and what connects them; and also a consistent imaginary word such as a poem or a novel. The INTp Gore Vidal has described himself, in his youth, as always wandering off into his own imagination and "automatically" creating a whole novel, which he then "just" had to put into paper. That is also Ni. So all of the definitions you mentioned are aspects of Ni imo. But I grant you, again, that the early definitions emphasized too much the "time" thingy, which makes no sense with the INFp "romantic and dreamer" aspect.
Adding to that --
A Ni dominant has no problem with remaining a long, long time in Ni mode; for them, far better to do that than worry about pointless, changing, "factual" data (INFp) or about one's role in the context of social interactions emotionally (INTp).
A Ni HA type sees the value of doing that, but keeps wondering whether they're not doing it too much and if they should not get going.
A Ni dual-seeking type likes people who do that because they could restrain a bit their own impulsiveness by thinking of the consequences.
A Ni PoLR type sees no pont to that at all. Wander off in your thoughts? Fine, but only if to solve the problem that's in front of you -- all the rest is self-indulging in pointless and lazy "daydreaming". Ni my ass! Get to work!