Or maybe it’s been proven to have feathers.
Short answer: Maybe, Carnotaurus, and yes.
Long answer: It seems right now that feathers are quite possibly the norm for all dinosaurs, with the discovery of feathers on Psittacosaurus, Tianyulong, and an unnamed Siberian ornithischian. While we don’t have much direct evidence, what we can tell is that all coelurosaurs almost certainly had feathers, and with Sciurumimus possibly all tetenurans (though its exact phylogenetic position is debated). I would say that with current evidence, it seems that feathers are basal to all dinosaurs.
The only giant carnivore definitely confirmed to be covered predominantly in scales is Carnotaurus. A few tyrannosaurids have also been reported to have extremely fine scales; however it is probable that they were covered mainly in feathers. Scales on Carnotaurus also don’t negate the possibility of some feathers- they can grow between scales (And dinosaur scales may actually be modified feathers!).
I don’t quite understand this last question. As dinosaurs are descended from reptiles, they are a subset of Reptilia (or Sauropsida).
The BBC recently posted this infographic. Let’s just ignore the fact that their pterosaurs lack tails and focus on the fact that their Hatzegopteryx is Rodan.