Yea, there are ceramic knifes in real life, they do very well, harder then most metals, and therefor require less sharpening. Did you also know there are ceramics that conduct far better then metal are notibly low temperatures? Ceramic is a very wide term these days, and just because dwarfs can make a few types of ceramic dosn't mean they can preoduce the type used for knives.
If I were to weaponise ceramics , I would mod in clay golems and make then tamable, with the trainable tag.
The thing about "Stoneware" is that it can be literally described as "Man-made stone" (or dwarf-made in this case). You take the sand, silt, or clay of certain types of stone, and melt them at extreme (1000 degree Farenheit or so) temperatures until they basically hit semi-molten state, and congeal into a stone in the shape you wanted.
The problem is often that stoneware is very difficult to make very thick - you have to make the body of the material you are working wet to work it, but that moisture needs to escape when you boil it at the extreme temperatures you hit when baking it. This is why stoneware, and to a greater degree, porcelain, need to be fairly thin.
Making stoneware have properties functionally similar to actual stone makes perfect sense in this regard. I could see a "ceramic bolt" being manufactured as a means of producing weapons on non-metal-bearing maps. That, or obsidian or even flint-based arrows. Flint can keep a sharper edge than steel, at that. Sure, a ceramic bolt would break after one use, but that's an acceptable loss you have with bolts already, anyway.
As for non-metal armors, there are some ways to do it... I know of rattan armor, which was supposedly used in Ancient China, which was composed of a bamboo-like vine for the main bulk, then treated with oil to harden. You could possibly layer in some ceramic plate inside of a rattan or similar flexible fabric that could act as a shock absorber, and reduce the odds of shattering prematurely, or at least, make sure the fragments stay in the armor, and keep providing some protection. Even then, you'd probably have to discard it after every battle, but since vines and clay are a renewable resource, that wouldn't be much of a problem.