This is a question about splitting a verb with a clause, not a word. Thus, it's similar to but different from usual verb splitting. Or, rather, I'm wondering if it's different enough to have its own term, and its own rules for correctness.
For example, for the two sentences ...
Our main participation will be, as usual, a demo.
Our main participation will, as usual, be a demo.
... (1) is there a term for the kind of verb splitting going on in the second sentence, and (2) are both considered more-or-less equally correct, as with regular verb splitting (by a word or words)? Or is the second form considered incorrect, or significantly less correct?
I have reviewed these previous posts (and their references):
Name of phenomenon when you place a word(s) between 'will' and the verb?
I have also looked about for rules on placing commas, and while nonessential clauses are covered, this exact circumstance is not; e.g.: