Congratulations! This approach is fundamentally feasible. There are a number of details which would have to work differently than what you outlined, with a couple presenting serous problems - but the broad approach does work.
Let me go over those details first.
Use Laws to specify that each and every plant, along with each and every microbe, and each and every fungus within your Dantian is an extremely single-minded unimaginative instinctive Cultivator
A Cultivator is someone who uses their Will to create and shape an Inner World. It is axiomatically impossible to have a Cultivator without Will, and a will implies an ego. You might be able to turn up focus and turn down imagination, but at the end of the day the creations HAVE to be sapient; you can't have literal cultivation machines.
You might be able to define the starting conditions, but the way the Will grows, especially once separate from the body, is outside your control. Of course, in practice defining the starting point plus exterior conditions is enough to get most cultivators following the path you've lined up for them; you might not be able to control any individual Will but creating trends is doable enough.
Use Laws to specify that each and every plant, along with each and every microbe, and each and every fungus within your Dantian is an extremely single-minded unimaginative instinctive Cultivator
To do this, you would need to make every plant/microbe/fungus sapient. The Law of Life does allow you to get life-forms which aren't completely bound by normal physics, so it is possible to get even tiny bodies to support fully sapient minds (and therefore generate corresponding Wills), so that part is doable.
If you actually want them to form a Dantian, though, you are going to run into a problem with most of the life you mentioned. A Dantian always has a fixed size - approximately 1.1 inches (2.8cm) in radius, or about 30% bigger than a golf ball. A human cultivator can make space inside their bodies for a such a thing, and then move their Will and Qi there to form a Dantian; a microbe isn't going to be able to pull it off for lack of space. Furthermore, presumably you want your body to keep working even with part of its area displaced, so that means you need more than the ability to physically fit a Dantian; you need to be able to do so without displacing anything critical to life.
Point being, if you can't fit a gold ball inside a creature without killing it, letting that creature cultivate won't actually let it walk the road of cultivation past the core-formation breakthrough. This rules out any microbe and the smaller plants/fungi, though there should still be plenty of the latter two for you to work with.
Use Laws to specify that each and every plant, along with each and every microbe, and each and every fungus within your Dantian is an extremely single-minded unimaginative instinctive Cultivator
Every cultivator is an "instinctive Cultivator"; the Law of Cultivation basically gives beings with Will the ability to sense Laws and the broad steps needed to move forward with beginner cultivation.
However, instinct only covers the ability to sense the Laws; comprehension is up to the individual. You can't give a life form "genetic memory" of Law or the like; at best, you can make a life form whose body inherently uses certain laws, which would make those laws much easier to sense for said life due to the proximity of examples. If your idea is making plants which would be able to form a Dantian as easily as normal plants grow towards the sun, that isn't going to work; the plants would need to improve their comprehension first, and that is not going to be something you can build in.
cycling through Core Formation and Dantian dispersal as quickly as possible. Frequencies measured in the kilohertz may well be possible.
You don't want to do that. This generates no energy; if you create a Dantian and then immediately disperse it, all you get out is what you put in. You haven't actually "digested" any Grandmist at this point, so you haven't actually added any more net energy. To get net energy, you need to Manifest the Recursion law in the Inner World and start sucking down energy to expand it. At that point, every unit of energy you've pulled in to use towards cultivation means more than 1 unit released. (It is actually a pretty large multiplier when you have only the Existence and Recursion laws to support, close to 10x.)
cycling through Core Formation and Dantian dispersal as quickly as possible. Frequencies measured in the kilohertz may well be possible.
Core Formation by a beginner is something that will usually take minutes-to-hours, so you can't go that fast even if you wanted to. Worse, Dantian dispersal is a lot more difficult that you seem to suspect. Basically, the process of Dantian dispersal looks like this:
- Prepare a target anchor that you are going to be moving your Will to and which can survive a connection to your Inner World
- Perform a Lesser Ascension ritual, expelling your Will from your Dantian and into the prepared Anchor
- Destroy the Dantian which used to be your Inner World, releasing the energy within
- Spend time recovering from the moderate Will damage that a Lesser Ascension ritual implies (unlike a true Ascension, Lesser Ascension requires a bond between an Inner World and something that is NOT an Inner World, making the connection imperfect; accordingly, the degree to which your Will is transported out is also imperfect)
The last step in particular means that rapid destruction of one's Dantian is not realistic; the Will just can't survive that sort of strain. You have to build in time for recuperation.
The first step could prove a dealbreaker entirely, though fortunately the body itself can act as a passable anchor if significantly reinforced via the Law of Life. Of course, a body is even more different from an Inner World than a pseudo-dantian, which means even greater Will damage and required recovery.
new chunks of Reality come into being already containing these Biological Qi Engines
New Reality coming into existence can't include life (or more precisely, beings with Will), though the seeds for life to emerge can be there.
Unlike the Law of Oscillation this won't result in Desolation buildup, at least nowhere the Cultivator on top cares about, since the mini-Dantians on the second level of creation are being jettisoned almost immediately.
Yup. Nobody really thinks of Desolation in abandoned Worlds; "where do those Desolate Worlds go" is just the dual side of the "where does the Grandmist consumed to make Qi come from" question. Basically, it is an academic question at best.
See next post for how I imagine an Inner World set up for Energy Agriculture could look after the amendments noted above.