#2 Art is there in every culture - even the Harappan - and they do not depict war. Every other civilized (city based) culture depicts war
#3 tales yes - because the tales of Harappa are the pre-Vedic Indic tales that one can find in the Tamil Sangam or the Puranas
Maybe it was something they regarded as necessary but not glorious. We have very little art in any culture showing people digging latrines.
Are you sure?