I would be careful about reading too much into theories based on measurements of things underground, especially those made by ultrasonics, because they don't tell us much about temperature.
The reason such studies are done, like pretty much all science, is profit driven, folk speculating on how to make money, how to attract VC funding.
Dangling unprovable carrots is what I see is modern snake-oil. We see it done with outer space all the time, the carrot of colonising Mars is a classic example. There is nothing to stop profit driven players "With vision" doing the same with the interior of the Earth.
All of what you've put together here looks to me like theory which has to sit in context with the grand system of what we know about everything else, including something really fundamental, which we really do have a problem with, that is energy.
Iit all has to "stack up".
The system of energy is something misunderstood, again driven by profit, as far as I can see. Most of us are conditioned now to resist believing anything is for free, or is infinite (for all practical purposes), therefore we can't conceive some fundamentally important things, like propulsion without fuel, or energy without fuel. The first is important, but the second is existential.
I argue there are skills and tools which come from profit driven industry, which can, and are being brought to bear on the bigger scientific problems, in a non profit way, to assist scientists to come to the correct conclusions of what we know of all things. Those skills and tools are generally not known by many scientists, since after all we only have one lifetime to gather everything we know individually.
I know this because I have some experience of carrying out PhD candidate work, after a long time in industry as a model based Systems Engineer, my research was on a subject most suited to be carried out by Model based Systems Engineering techniques, but there was not enough expertise on those techniques in the academic community to be able peer review my work in model based form.
This is no bad reflection on scientists, like I said, we only have one life, to gather all we know as individuals, I can't claim to know everything a scientist specialising in any particular domain knows, but I do know about Systems Engineering, and as much about any subject as I've needed to know to build and/or analyse working physical systems involving the same.
Hence the reason I write in Medium now, to try to assist folk, including scientists, how to understand some fundamental things about the system of energy, used by nature, which we seem to be getting fundamentally wrong, due to the profit driven mindset. Again, knowing what I know now, II see this fundamental misunderstanding of energy as existential.
On those underground theories, some questions I would ask, is how is the energy needed for that life underground transmitted to it? On water underground, we know that there is a rising heat profile, which logically extends into Earth, rising to a maximum at the core, resulting in there being an awful lot of molten rock down there. How does that stack up with water, which can only exist as vapour under very high pressure above 100C?
On the oxygen produced by plants, it has to be related to the energy utilisation of plants, after all that is what the photo-electric effect is; utilisation of energy.
How that relates to water, is that there is energy absorbed during the production of oxygen, which also consumes water, and if we reverse that process, as we do using fuel cells, or by combustion of hydrogen, water also has to be produced.
So there we can see a key, how to provide and even transport fresh water as a by-product of our use of energy, in a solar powered hydrogen economy.
This is how nature works, it is solar powered and all by-products are put to use by other life, there is no such thing as pollution in nature, only we currently produce that, by deconstructing physical things nature created as fuel. The only fuel we can safely consume, with no environmental cost to Earth, is fuel we created ourselves from the energy of the sun, like hydrogen, because by that we didn't decreate anything created by nature.
The good news is we can create hydrogen with zero effort, other than the non-exotic materials needed to convert it from electrical energy from solar, instantly and infintely, relative to the time it took nature to create oil, again from solar.
I hope this doesn't discourage you from researching, and asking questions, we all have to ask some tough questions in our quest for truth, and survival of our species, and to me you have the right mentality, I like your thinking, and hope to see much more.