Tommy Bolin

An outdoor survival class I took in the 70's suggested that for treating diarrhea, which is life threatening in a remote survival situation, that a handful of ash from your campfire, mixed with water and consumed was a remedy.
My friend from high school was a Pararescue Specialist in the AirForce. His survival training taught him the same.

Deters slugs, place around edge of garden.

Finns clean the glass of their woodstoves with ash. According to my Finnish mother.

My dogs sleep in dry ash in the Fall. More to do with the heat stored in the ground and being very dry. Likely. Does seem to help with black flies/mosquitoes in the early Summer a bit if they let me put it on their faces. Anectdotal only. Your experience may differ.

SIPS are a decent building idea. As a framer I don't care much for their inflexibility of design. Big rigid rectangles, sized like plywood. Foam core bonded permanently to OSB, chipboard type ply.
Not nearly as eco/permie friendly as locally produced wattle and cob/daub. Some consideration must be given to off gassing of manufactured components, although that has been mitigated in recent years by production changes.
They spline together with standard framing lumber and 8d nails. Very fast. Great insulating value. Air tight. Shear rigidity, built in.
If you don't plan on lighting your house on fire, then don't confine your mind to the terror of toxic gasses. Make sure your electrical is up to snuff. Have enough water to handle your own situation until help arrives. If your house is burning, you have bigger problems. Stand up wind to watch the flames.
Like wise, don't confine your mind to the idea of needing a crane. 4x8 ft SIPS 6 in thick weighs less than 100lbs. That's a lot of wall. I've handled SIPS, alone, almost 12 ft long.
DryVit was a light, semi-flexible, stucco like plaster with some insulating qualities we used in Montana back in the 80's. Had some perlite in it, believe. The old stagecoach inn in West Yellowstone I helped build as a framer '88 or so has a bunch on the outside. Still there. The idea has been there forever, I'm sure you could do just as well now on your own jobsite. But you will give up some of the more permie aspects of cob, my guess.
Prefinishing stand alone panels would work, but you'd have a permanent joint and it's possible drawbacks to deal with. The panels referenced above are more likely to be infill in a timber frame type setup.

The idea of heat exchange/storage for a dwelling (therefore possibly greenhouse) was pretty well laid out more than 40 years ago by John Hait in his book "Passive Annual Heat Storage....". Explores heat(cool) transfer/storage through soil, and the 6 month cycle of earth temperature fluctuations according to outside air temps. Worth reading.
The house he frequently references was built in Missoula around 1980. The idea of using the earth/earth tubes to exchange/store heat in this fashion goes back into the early 70's at least.
Note that the charts/ideas posted say "average" temperature. Summer dirt two feet down in Texas will be nice and warm, my bet.
But cooler than your greenhouse maybe. Horny toads hide in the sand during the heat of the day.

As an aside, Bluff Valley Battery sold me the guts to refurbish my old Milwaukee 18V NiMH batteries.
Saved tossing a tool set I really liked when the proprietary batteries were NLA.

I like the fuel cart. I use a hand truck setup to move jump start batteries and tanks for the propane milkhouse heater when getting things running at low negative digits.
However, I belong to the stone axe simple tribe.
Have a really old version of one of these, along with the 12V hi volume DC version attached to the 120gal TidyTank I use to store diesel.

https://north40.com/fill-rite-cast-aluminum-heavy-duty-rotary-drum-pump

Not a siphon, but true pump. Moves tractor/hydraulic/engine oil, which your (especially if non-self priming) little DC pump may not. Cost might cause some alarm, they never used to be this expensive, but there's no deciphering which battery is 'best', no batteries to charge or replace, works in all weather, moves a startling amount of fuel in a very short time, no (infinitesimal) risk of explosion.
OP has already set out on the opposite course, but for any one else looking...... Eric's already replaced one pump.
You can't wear this one or it's non-existent batteries out.

Some of my thoughts.

permies.com/t/357816/Replaced-lead-acid-batteries-LifePO#3462378

I have 1500+-ah of series/parallel 24 volt L-16 type lead acid US Batteries. No grid here anywhere close.
Looking at Battle Born's website, for American tech, I would likely need about 15,000USD worth of heated batteries, to replace them. Mine cost, in 2023, about 2600USD through Oasis Montana, no sales tax, picked them up in Missoula, no freight.
LA batteries, for all their apparent shortcoming are:
Stone
Axe
Simple.
....and pretty dang heavy.
Been around for well over a hundred years. I'm not sure I want a battery that takes it's own brain to function, even if that brain is American made.
We leave our home 4-6 weeks in the early winter, the temps inside get down to about 10F.  Therefore the self heating batteries. Our winter sun is actually decent. My snow covered yard opens to the south, our lake freezes/snows over. One big reflector. Solar panels work better in the cold.
You could spend less for LiFePo I'm sure. But if you told me you believe the circuitry and safety features of some cut rate Chineese battery you bought on TEMU/AliBaba/Amazon, for which you will have NO recourse in 2-4 years, were equivalent to the units sold by a Nevada based company, I would say my belief is you are delusional. In my mind because of complexity and 'newness' of tech, the lithium is not yet close to proven.
Go to the Battle Born website and look at the list of tests and compliances they subject their batteries to and provide the same data for the batteries you seem to want to recommend to me.
I may or may not not get 3000 cycles to death a LiFePo battery seems to promise, but I never run my batteries to less than 70%, and the 4v lead beasts these batteries replaced lasted about 30 years. I don't kid myself that these batteries are the equivalent of the 4V KWatts we had, but I also could apparently replace my US Batteries like 5-6 times before the cost breakeven for lithium is approached.
My only caution for a high capacity LA like these is to mind the charge rate they like for bulk charging. These batteries like almost 40A of charge to begin.
300W panels are cheap, charge controllers and cabling are not, doing that on a budget is tough, possibly not having to panel up is a plus for lithium. Some of the current charge controllers or control/inverter options no longer support three stage LA charging, something else to consider.
Battery prices in Canada are quite high. I can buy in the States and pay the 10% duty and come out money ahead, even with currency conversion.
When your lithium batteries are 15 years old you can tell me how wonderful they are/have been.
I'll be waiting/listening.

Is not the idea behind John Hait's work ' Passive Annual Heat Storage' and the original early 80's version of the house/concept built in Missoula, MT. to redirect the water out of the earthen mass next to the house, keeping it dry?
As well as using the mass of the dry earth to store the heat rather than attempt to insulate the house from a wet heat sink, tempering indoor temperature swings, and taking full advantage of the environment by storing the energy of the summer sun, rather than being forced to shade it out?
I have built hundreds of houses since the 80's, but never any sort of earth shelter, so first hand I don't know, but Mr. Hait's ideas make brilliantly simple sense.
I am just starting an earth sheltered greenhouse up here, the work of John's group is good part of the basis for my plans. I'll have my own (informed) opinions in the next few years.
The .pdf of that book is around, I would suggest reading it.

10 ft. tall is pretty ambitious for a self supporting wall, as in cantilevered up from earth. A lot of sail surface. Be pretty wide at the bottom, have a lot of mass or be firmly anchored.  A 'wandering' wall would be a little more self supporting than a straight fenceline.
Don't know where you are at, but I worked up in the mountains out south of Carlin years ago, remember the wind can get clipping around Elko/Eureka at times.
Having said that, snowfences work, there are some along the 93, and you'll see them up in Idaho and Montana. Just need a fair amount material to build.

Without a roof to shed rain, or a truly waterproof cap, you'll have to get around to the idea that water will eventually find it's way in to your earth or straw.

True straw is the second cutting of grain, the stalk. Light, hollow, fairly inert. If the your 'straw' is being grown, and cut whole, it is more like hay. A lot of energy and biomass in whatever the seedhead contains.
Those are my first thoughts.