Balder: I agree that "plenum" is metaphysical -- but not necessarily in the sense critiqued by postmetaphysics. Here, I was thinking of something like Harman's description of reality as "jam-packed with objects," where every form, (momentary or eons-long) relationship, process, etc, is "object," and where every object also withdraws. So, this would be a different meaning of "fullness" (plenum) than a fully present super (ass)holon. Granted, I think Bryant handles the notion of "withdrawal" better than Harman. A model like this also needs to handle something like "space," in my opinion. (Harman does so, for instance, by positing "space" as an emergent feature of emergent object-relations.)
Weird association but when I hear the word plenum I associate by sound the word frenulum.* Since the latter serves to functionally allow flight by connecting the fore and aft wings on certain insects, perhaps to distinguish the bad from the good metaphysical plenum we might call it plenulum? This way it can take flight from bad metaphysics?
* It is also "a thin strip of flesh on the underside of the penis that connects the shaft to the head." You knew there had to be a sexual meaning in there if I'm using it. Aka the "banjo string." Also relates to female genitalia.
Balder: An odd association, yes, but quirky enough that I like it. It echoes "pendulum," too, which might be seen to imply the tai chi swing between (not-)empty and (not-)full...