Yeah, their uniforms would be pretty similar, though the Austrian uniforms would typically have a more fitted tunic, insignia on the collar tabs and flared riding breeches. But I'm not really sure if Austrian cavalry received helmets at all during WWI, as Austrian helmets were generally issued only to troops serving on the Italian front and the small units sent to the Western Front. Almost all of the cavalry served in the East and the Balkans, without steel helmets.
As for Turkish helmets, again I'm not sure if cavalrymen received any helmets. The Germans did produce a specialized form of the Stahlhelm for Turkish infantry assault troops, without a front peak (ostensibly so the Muslim soldiers could pray in a proper manner while wearing the helmet). This only appeared in 1918 in limited quantities.