Panelo, I believe, was at Law School with Duterte. So, though it may appear that his appointment is akin to "jobs for the boys" ...... to my mind, the selection was, in all probability, based on the guy's reputation as a top-notch lawyer - a factor most likely to've influenced the decision of a shrewd President elect.
Panelo, moreover, was the bloke who sent *Trillanes "scuttling away with his tail between his legs" after the *latter had demanded an investigation into the bank accounts of Duterte.