I personally wouldn't heat the juIce. I would make my concentrated brew then dilute with apple juice to hit the bittering you are shooting for. store bought already pasteurized so just open and pour in. Fresh press throw a campden tablet in the juice let it sit at least a day then throw it in. Less you heat things like juices or honeys the more character you retain ImoI would agree, with the caveat of "depends what you're looking for". Fresh cider gives much more "fresh apple" character, but heated apple juice gives you more of an apple pie/mulled cider apple character that is a bit different, but still has its place.
While we're on the topic of creative ways to add apple to beer, you could also boil the juice down to a syrup and add it like a sugar addition or candi syrup. I boiled down a gallon of juice down to syrup to chapitalize some hard cider this fall. I bet apple syrup would also make a nice apple tripel.