Voice acting isn't even worth mentioning. All stories combined, there's only a few hours of spoken dialogue for the player character, most voice actors get that much done in a couple of sessions. And refitting armor on new models is simple (I know that from personal experience), though in case of Tengu, most boots and gloves will require remodeling. Not to mention the headgear. Animations will require some work, but nothing that professional animator couldn't handle. It's nothing to get hung about.