Look, I'm at least as fond of the idea of ubiquitising hemp as a commodity as anyone, anywhere, and having it replace all manner of less-sustainable choices.
But it's not the best solution for every problem.
What I suggest is that whatever solution you come up with is designed to work with substitutions made in place of the hemp hurds. That way, if you happen to be close to a source of hemp hurds, you'll be in a prime position to take advantage.
And if you happen to be close to a clean, similarly useful waste stream that is not hemp, you'll still be able to take advantage of it.
I would treat the rocket stove processed oyster shell question as a separate one. It sounds like it would work, but I would also look at the chemistry involved, and see if it is possible to do in a retort, similar to what might be used for the making of
biochar. You're assured of keeping more cooked oyster shell that way, and you can direct an overpressure valve back down into the burn chamber.
Another useful thing lime could do for you is to stabilise rammed earth or compressed earth block mixtures. There are many places where the soil mix is right, or can be easily amended with nearby resources, for the making of rammed earth or compressed earth block, and stabilised with 10% lime or portland cement, can exceed the standard tolerances of
concrete.
I would focus on using the hemp, properly treated with borax and
diatomaceous earth against insect infestations, as insulation.
-CK
A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.
-Robert A. Heinlein