Yes. However, it is not apparent which inferences are possible to make with this kind of sensor data. How invasive might this become?
Brain-wave-scanning kind of invasive. FB (and advertising in general) will continue to become ever more invasive until it meets a limiting factor. That limiting factor will possibly be legislation (just not in the US because worshiping the Dollar overrides anything and everything else).
No, I don't think it unlikely that the next-gen Oculus might do this.
If this weren't invasive, they wouldn't be doing it. What use would random data be to Facebook? Also, it is irrelevant: if I buy a VR set I want to use it for whatever I see fit, not get hooked into some data collection machine. How is it that we have come to accept that in order to use products, that we buy even, we have to hand over lots of data?
So they are not breaking any laws while still targetting you for owning the unit.
They'll try to figure out if you have any kind of disability.