Happy New Year Meghdad,
I do not know the answer to your excellent question, but here are my thoughts.
In all the languages I have studied, even those closely related to English, it is hard to translate the terms that cover these concepts. The interior world is cut up into different parts according to the language and the culture behind it. In other words, the problem is not unique to English and Chinese. For me, the term Shen (神) covers some of what I mean by "mind," "expression," "focus," and "spirit," but sometimes these words are not appropriate translations. Chinese also uses xin 心, yi 意, and jingshen 精神 for some of these concepts.
From what I understand of the world view probably held by the writers of the classics, Shen was thought of as the clearest, highest form of Qi (energy/matter). According to most philosophers, humans have Shen, but animals do not. This aspect of Qi cannot really be translated into English, since the cultural heritage of the core of native English speakers thinks of spirit in opposition to matter, rather than as the most refined expression of it.
I would not like to think of Shen as correlated with merely one of the five elements, because that would lead me to think that strengthening it would lead to imbalance. I therefore would favor the second of your three options, with the major caveat that the English word "spirit" and the Chinese word "Shen" often do not refer to the same thing.
I also consider the terms "Shen" and "Jingshen" (or Jing Shen)(精神) to be different, as is reflected in your translations. The exact interpretation of the second term is problematic for several reasons.
First, it is still not clear to me whether 精神 should be interpreted as one word ("Jinshen") or as two words ("Jing Shen"). The Chinese characters are, of course, ambiguous. As the two words "Jing" and "Shen," the expression would form a grammatical compound describing a unitary concept made up of related items. It might be translated into English as "essence and spirit" or more clumsily as "essence and spirit stuff."
As one word, "Jingshen" can have two almost identical pronunciations in standard Mandarin. One leaves the "shen" syllable in a neutral tone as "jīngshen," the other gives it a full second tone as "jīngshén." The first is used for the common meaning "vigor or vitality" (表现出来的活力). The second is used for the intellectual meanings "spirit," "mind," and "consciousness," (指人的意识，思维，情感等主观世界) and also for the meaning "gist" (内容的实质所在；主旨). (The Chinese I use is copied from the Chinese dictionary I have on my Pleco App.)
Regardless of the linguistic niceties, for me, there are two very real practice questions.
First, how should we interpret the following:
What one trains in Taijiquan is the spirit.
(8th Principle, as translated by Louis Swaim)
Rather than the word "spirit," I would use the word "mind" for my practice, because it matches better my cultural understandings. If I train my mind correctly, my body will follow along naturally. Training my mind, however, must involve not only mental activity, but physical activity. For Tai Chi, purposes, mind and body cannot be completely separated. It is really two aspects of one thing. We just need to focus more on the mind aspect of it.
The second practice question is how should we interpret the word 精神 (jīngshen or jīngshén). What is this thing we are supposed to "raise" or place our "intent" on? The answers I like can be gleaned from two sources: Barbara Davis's book The Taijiquan Classics: An Annotated Translation Including a Commentary by Chen Weiming
, page 140, and Paul Brennan's Translation
of 太極拳術陳微明 The Art of Taiji
Boxing by Chen Weiming, Part 4, near the end.
The first text says:
24. The whole body's yi is on the spirit (jingshen), not on the qi. If it is on the qi, then it is stagnant (zhi).
25. When one has qi, then one will not have li (strength). If one has no qi (wu qi), then there is pure hardness.
Chen: Taiji is carried out purely with the shen (spirit), and does not set store by exertion (qili). This qi is post-heavenly exertion. Nourishing qi is pre-heavenly qi. The qi of movement (yunqi) is [a sort of] post-heavenly qi. Post-heavenly qi has an end. Pre-heavenly qi has no limit.
Notes: The whole body's yi is on the spirit. Some read "The whole body's yi is on storing up the spirit (xushen)."68
When one has qi. This line is very difficult to interpret. A variant reading offers "Those who esteem the qi have no li; those who nourish the qi (yang qi), pure hardness."69 The Wu/Li Classics have the same wording for this line as Chen Weiming's version.
Zheng Manqing [Cheng Man-ch'ing] uses this phrase in a discussion of the highest level of taijiquan accomplishment:
These words are very strange. They imply that the qi is not important, and in fact, it is not. When the qi reaches the highest level and becomes mental energy, it is called spiritual power (shenli) or "the power without physical force" (wu li zhi li). Wherever the eyes concentrate, the spirit reaches and the qi follows. The qi can mobilize the body, but you need not will the qi in order to move it. The spirit can carry the qi with it. This spiritual power is called "divine speed."70
By the way, I strongly recommend buying this book for those with a passion for Tai Chi theory.
The second text (from Paul Brennan's excellent site) says:
Throughout the body, the mind should be on the spirit rather than on the energy, for if you are fixated on the energy, your movement will become sluggish. Whenever the mind is on the energy, there will be no power, whereas if you ignore the energy and let it take care of itself, there will be pure strength.
Taiji is all about the movement of spirit and does not emphasize the physical effort of acquired habit. The energy of letting energy maintain you is innate from birth. The energy of moving energy around is an acquired habit. The acquired energy keeps finishing. The innate energy goes on and on.
The more one understands of the traditional Chinese worldview, the easier it is to understand these thoughts. In my view, some people do not research enough or else overemphasize Chinese medicine, which is only one type of thread in the tapestry of thought making up these views. For these reasons, I have very recently been contrasting potential energy with kinetic energy to provide a scientific reference for interpreting things such as:
養氣之氣。為先天之氣。運氣之氣。為後天之氣。後天之氣有盡。先天之氣無窮。The energy of letting energy maintain you is innate from birth. The energy of moving energy around is an acquired habit. The acquired energy keeps finishing. The innate energy goes on and on.
If I had to restate this, I might say something like: Your capacity to store and use potential energy is inherent in your body's position, configuration, and state, while your ability to manage kinetic energy comes from the ability you acquire to use your muscles and move your limbs around with speed and power. This acquired ability is limited by the start and stop of the motion itself, as the energy of the motion dissipates. The inherent energy of position, configuration, and state goes on and on, as the body simply oscillates from one state of potential energy to another like the springs driving the hands of a clock.
These are just my thoughts. I hope they help.