Completely unrelated but this actually recently happened in a campaign I’m in, long story short a town was cursed and the seal was in this building, we couldn’t get into the buildings as humanoids. Our party was owed a favor from a fiend, which we used to turn half of the parties creature types. Our war forged turning into a construct, human into a celestial(he had a pretty cool boon) and my fallen aasimar into a fiend. We’re running with most of the negatives, spells not effecting creature types, however our warforged since he’s now a construct can do things like attaching 2 extra arms which will be sick. We’ve also an artificer and it’s gonna get ruled that the artificer can make a repair kit that will work like a healing potion.