I think most of this info here is correct, but as I mentioned on the first posts, the info I collected there are to supplement official bio and lore that are mentioned in the game. I try not to list info that are already presented in official sources.
EDIT: Re-reading your post, I just realised that you were just listing out some Theonite facts rather than suggesting some entries to add to the first post. Whoops. Editing below post accordingly.
Anyway let me go through these one-by-one.
- Parasites and Living Weapons are said to be created using Theonite. Some are mentioned to use or feed off Theonite to strengthen their powers.
Theonite is indeed used to create Living Weapons, but not Parasites. (However it is unclear how Artificial Parasites are created at this point but likely Theonite has something to do with that.) Both do have connection to Theonite though. More on this later down the post.
I'm not sure where the info that some Parasites and Living Weapons feed off Theonite came from though? It would make sense but I don't remember it being confirmed. Can you let me know your source?
- Isaac has been using shards of a unique type of Theonite he discovered in his search to time travel.
- Anti-Skullgirl Lab 6 specialized in Theonite research, to discover the full capabilities of the material.
- Dr. Avian used Theonite to balance out Peacock and prevent soul contamination, a mental corruption that occurs in people possessing multiple (synthetic or natural) Parasites.
- Theonite has a big involvement with the Skullgirl. Using a Theonite Resonance Detector, Peacock and her crew were able to close in on the Skullgirl.
Yep these look correct to me.
- Theonite resonance is a spike of energy that comes from strong constriction of Theonite. Several spots in New Meridian have been mentioned to contain Theonite resonance. However, the biggest source comes from the Skullgirl herself.
For this last point, as I previously mentioned, we should probably make clear the distinction between Theonite the mineral and the (currently unnamed) substance that makes up Theonite, Parasites and Living Weapons.
Since I'm on the subject, in the real world, the "-ite" suffix used in chemistry is used to denote a negative ion, or compounds that contain such ions. For example, Nitrite is a molecule containing nitrogen and oxygen atoms, with a -1 charge.
I doubt Alex was looking at the technical scientific definition of an -ite though, so most likely he just used it to denote that it's a type of mineral. :p However, what I think he is getting at is that Theonite is simply the mineral form of a more fundamental substance that makes up Parasites and such related beings.