Well, if space-time is considered matter, then I guess I should add space-time to the elementary particles as what is matter. But the question of whether or not positions still remain.
Please try to keep focused! We were talking about the use of the word "material", not of the word "matter". We're not debating about the word "matter".
So, sticking to current science as you urged us to do, I will assume that science does not regard spacetime as matter. Yet, we use the word "material" to refer both to matter and spacetime (or perhaps more accurately to all spacetime relations between distributions of matter over spacetime). I take it that all material properties are considered by science as dependent on the spacetime distribution of quantities of matter. You cannot make any observation of matter except through these spacetime-dependent properties. So, the word "material" really means that spacetime and matter cannot be considered in isolation of one another, and this is science. All you can say, and everybody I guess would agree, is that some material things are not matter but something else, i.e. spacetime, or spacetime relations between distributions of matter over spacetime. Yet, from that, you want to say that spacetime and spacetime-dependent relations are not material. But what's wrong with just accepting that these things are material but not matter?
EB