Which one is correct out of the following? i. Perhaps he has done it. ii.Perhaps he would have done it. Can we use 'perhaps' with 'would have' for a thing that we speculate or doubt was done by someone? Or does the word 'perhaps' fulfill the need of speculation thus we simply use present perfect tense is situation like this?
Yes, because they refer to different things within the sentence.
Perhaps refers to the narrator's inquiring of 'his' actions.
Would have refers to a conditional action, if a different scenario had played out.