As for house elfs in general during the war, most will probably serve their masters during the war and therefore be on which ever side their masters are on ( this does not bode well because if house elfs come with big mansions of wizarding families, many of which seem to be the very ones with strong wizarding ties and pure blood sentiments).
however some elfs, like Dobby, may find this war as their release from evil masters, but i think they will be few and far between.
