When a player successfully rolls a knowledge DC, are they considered to have a "level" of knowledge about the subject, such as common, uncommon, and rare? Thanks!
In a word: "no"
Your rules-rigorous terms are pretty much limited to talking in terms of DCs, "is trained in", and "has as a class skill."
If you want to talk about general familiarity and so forth, there's nothing stopping you, but there is nothing rules-rigorous like what you're talking about. If you want to see good examples of this, check out the scry and teleport spells.
Also, slightly off topic: you are risking getting too specific about your item, which breaks the rules on preserving anonymity. Just a friendly FYI. :-)
You probably either want to set up a knowledge check DC, or simply base it whether or not the character knows *anything* about given creature at all.
Also, to repeat the chorus, be careful with revealing this much. It might very well give off your item. There's just no way to be sure that there'll be another not-yet-submitted, knowledge based item.
Best of luck.
