Language is not algebraic and cannot be easily tabulated. And that's a blessing. A universe in which linguists would also be mathematicians is a perfectly Orwellian one, thank you very much.
Concerning the first part of your question, the City Beautiful Movement comes to mind:
The City Beautiful Movement
You furnish a number of examples of postposition ...
For me, I might pause, I might carry on without a pause, I might say "dot dot dot" or three short "hmm hmm hmm" to denote that there's an ellipses. For reference, I speak Canadian English, but I hear a lot of Americans doing this too.
I find it quite acceptable (though 'acceptably punctuated' rather than 'grammatical' is the standard way to describe this on ELU), if it doesn't lead to non-negligible confusion. How many different ways is the overworked comma used, after all?
Finding a supporting 'authority' (there are no absolute authorities) proved easy. A caveat about cavalier usage was ...
I am a native speaker and I think this is perfectly acceptable and understandable. It might not be appropriate in really formal settings but the ellipsis is pretty clear, and the meaning is plainly conveyed. I'd recommend using a comma rather than brackets though:
She is interested in philosophy, especially of mathematics.