the first one is correct, if the text says his verbis territus.
regarding the second one, non mortuus est means "did not die" or "is not dead" - it cannot mean "was not dead" (mortuus erat/fuit)
the third one... it's just "a cup of wine too hot", no "is". then you translated venenum as vinum. positum erat is pluperfect, so "had been ___ed" (not "having been ___ed").
flebile nescio quid queritur lyra, flebile lingua murmurat exanimis, respondent flebile ripae