"essence" : this is also something that can "arrive" and "settle" in a person, and is required for life
It should be noted that "Qi" and "essence" are very intimately linked, if not actually referring to the exact same thing (but then why use two names?). Both Qi and essence are required for life and can dwell within the body, and there are lines apparently referring to the "essence of Qi" and the "Qi of essence".
It seems that the Nei Ye may be saying that Dao, De, Qi, and essence are all-pervasive spiritual things (as opposed to concepts) which are not inherently within us, but which can be obtained by taking (and keeping) certain mental/emotional attitudes. However, it is also possible that the Nei Ye is using these terms to attempt to explain by allegory and metaphor the various feelings experienced as a result of the meditative practices of the writer(s). According to LaFargue, this interpretation is supported by the inconsistent "definitions" given of the various terms (and the relationships between them), and by the sometimes experientially similar descriptions of different terms. The readers can decide for themselves.
"heart/mind" : usually translated as either "heart" or "mind" (the symbol means both), it seems that the ancient Chinese may have considered the heart to be the place of understanding, perception, and awareness, so "heart/mind" seems to be the best translation
"form" : this appears to sometimes refer to the physical body, but often not, because the "form of the heart/mind" is referred to several times
"properly aligned" : literally just "proper" or "correct", this is taken to mean "to bring into a proper or desirable relationship"
"regulated" : to be orderly, well governed, under control; guided by certain rules or principles
"confused" : the opposite of "regulated", and the normal state for most people; caused by getting caught up in the ten thousand things, love and anger, worry and happiness, etc.
"thought", "intent", "desire" : regardless of what it is called, as far as the Nei Ye is concerned, it is sometimes a good thing, sometimes a bad thing; it seems to be a mixture of both thought and feelings (similar to "heart/mind"); "intent" is perhaps best because that has connotations of thought and emotion, but "thought" and "desire" sometimes work better in English
"equable" : while the symbol literally means "even", "equal", "calm", equable means to be steady, free from extremes, serene; not to be confused with "equitable" (unbiased)