I like the first half as a slightly stylized translation. Strictly speaking, ferus is adjectival and you did not translate et (in line 2) ... for all I know you did that on purpose.
You tripped up on the last two lines a bit:
nata (sunt) is a verb, taking caedes and proelia as its subjects.
(hominum) generi is dative of (dis)advantage, not genitive
aperta est is passive, and can only have a feminine singular subject (aperta est). you also incorrectly translated it as present, which it cannot be.
brevior is comparative
flebile nescio quid queritur lyra, flebile lingua murmurat exanimis, respondent flebile ripae