introverted perception and judgment
I get the sense the way introverted perception is dynamic, judgment static, is not very well-presented. It seems like there's a tendency to associate Ni with forecasting trends to explain its dynamic nature, but this seems totally unnatural and out of nowhere.
Here is how I see the relation between these two. Introverted perception is that factor of perception which conveys an image while emphasizing subjective factors more than objective ones. Hence, when an objective stimulus awakens the attention of some party, for the subjective perception to work, the attention must proceed not to merge with the object which transmitted the perception, but to the subjective imagery evoked. To do this, generally the mind synthesizes the image based on various subjective impressions existing already, and even vague glimpses of possible ways these could unfold - it takes all these and puts them together using spontaneously formed associations which are subjective in nature.
You can see images from various points of the subject's past experiences and potential experiences converging in the perception, so as to distance the subject from that factor of perception most immediately released by the objective stimulus. This produces the so-called time-orientation.
When the objective stimulus hits, on the other hand, the introverted judgment, being an introverted process, to truly kick in, must negate the perceptive tendency once the individual has directed the attention inwards. Thus, naturally when perceptive associations bleed into the present from past and future, threatening to suppress the objective image by converging into it continuously, judgment extracts which factors remain constant in the stream of subjective constants. It forms a body of ethical or logical principles which either apply in a given situation or can be expanded to include it as a possibility.
To illustrate how reason plays with objects and subject, we can think of Te/Ti. Te works with objective activity, that is, basically procedural/programmatic information about objects. The idea is that to describe the dynamics of objects, one must be able to say, given two objective states, the process leading to the transformation of the two. Can this be expressed rationally? Yes, by algorithms, hence why Te is algorithmic logic. With subjective states flowing from one to another, bleeding into each other, it gets tricky on the other hand. You could naively think to describe an algorithm for these procedures, but that doesn't work now, does it: because there is no object moving from state to another. It is your subjective consciousness which is moving, expressing how seemingly distinct objects exhibit a relatedness through your subjective consciousness moving from the perception of one to the other. We are not, in a sense, really trying to describe the movement of subjective consciousness here so much as describe the relatedness without having to experience it. In an objective situation, say there are two distinct objects, and one could infer a relatedness between them which isn't objectively given a priori, meaning we do not see an objective path from one to the other, but we do see a relatedness nonetheless, this connection between the objects must necessarily be subjective. At the level of perception, it happens initially when a different experience (whether imaginally generated or actual) converges into this current one, creating the sense of relatedness. That is, our experience of the objectively transmitted perception has suddenly grown divorced from objective factors. This is where static introverted judgment tells you what subjective relatedness is being seen. By getting rid of the time variable, we imagine that the relatednesses which could converge from mentally generated imagery onto the perception of the two objects are rendered inherent to the picture of the two objects. Clearly even if we didn't know this, by definition this must be an introverted function. How to remove the time variable? We must place all convergent associations into fixed categories, meaning, we must name the relatedness (what happens for instance when you take a person, who you experience daily, as slightly different, due to their just living a different phase of life, and name them -- they become one person, they become identifiable, even if this sense of identity is in a sense just something we created - hint, this kind of happens with typology, but obviously we do find this useful in our world). This is how things like introverted thinking work. Of course, usually there'll be more than two objects, more than one interrelation, so there'll be a web of logical associations fixing what can be said about these categories. It probably works similarly with ethical reasoning, except the rational connections between categories will be ethical in nature. For instance, a certain state of relatedness/attraction between categories implies certain ethical statements and logical statements.
Let me study what you're saying, exactly. You're writing is analytically beautiful!
First, Ni "imagery" for me is almost always something that is summoned. So much so that it gets me into trouble sometimes if I admit what I'm truly able to remember. How? Well, I remember what I've done, because as an introvert with an introverted ego, I only want to do as much as I can subjectively digest - so my goal is to work closely and intimately with what I'm doing, and by proxy, I will remember what I've done specifically. (I can recall what others would have simply pumped and dumped, because I store information away subjectively like a puffy-cheeked hamster; this makes forgiveness very difficult for me.) If someone were to ask me, "Do you remember _____?", I would most likely be able to say that I did, and then if I felt safe enough, I could give specific details about it or explain what happened, because I was sitting there observing passively all along like a fly on the wall.
Images do not just flash in front of me like a projector or PowerPoint presentation. Who could live like that?! I remember the spatial orientation of objects whenever I need to, which for me, is a lot like on Google Earth. I don't organize things in how I associate them, though, but rather, I organize things in how closely I relate them to each other. Therefore, something is either closely related or it's not, with no exceptions. Unlike a rule or category, I don't include or exclude something based on the object itself. For example, the stuff that I've used most recently or the most frequently will be in the front on the refrigerator, and it's the same in my bathroom cabinet.
As Ni ego, I naturally want to retain information internally like a data bank, and I advantageously recall it whenever it's useful or relevant. I'm almost like an introverted IEE "reporter" who is wading through information with Ne, but instead, I wade through information with Ni. But unlike an IEE, whose third function is Te and hidden agenda is "to know", I don't crave "knowledge", necessarily. I want to be "in the know" in order to be prepared for what comes next. More often than not, I want to avoid (Ti) being caught off-guard and then responding inappropriately and becoming embarrassed (poor utilization of Fe)! Not knowing what's going to happen in the future really bothers me, and I believe this is mostly attributed to Ni ego. The difference between myself (IEI with Ni ego) and an LSI with Se ego is that I want to protect myself and others (as "the victim") with data whereas an LSI would want to use information to create an advantage for himself and others (as "the aggressor").
I could go on to talk about the use of Ni in ILIs in detail, but to save time, the use of Ni for an ILI as "the pseudo-aggressor" is a blend of what IEI wants to accomplish as "the victim" and what LSI wants to accomplish as "the aggressor".
This is how I always thought of it, might be completely wrong
Ni: Uses internal thoughts and meanings of things to create ideas and expound on the possibilities of it. Goes deeper and deeper using subjective experiences as branching points
Ne: Take an external object and create ideas on the possibilities of that object. Fleshes out that idea to an extent but will just as easily generate more ideas when another stimulus presents itself.