Velostat sensitivity to temperature
I don't believe it will be any more sensitive to Temperature than any other resistive material, assuming you don't heat it or cool it enough to substantially  change the material properties of the matrix.

That said, I actually find Velostat to be BARELY sensitive to pressure along the scale of what one would normally use a force-sensitive resistor for.  You can get a fine pressure sensor, though, by taking advantage of the nature of the connection between the Velostat and whatever conductor you use for the outside of the sensor (like copper tape), and how that connection improves under pressure.  If I use copper with conductive adhesive on it, the connection is uniformly  good, and I don't get much pressure sensitivity.