Technically the speech bubbles could also tell us the Voices are giants (cf. the speech bubbles of frost giants and death giants). The good thing about the erratic wind is that if it is, in fact, caused by wings, we can safely exclude the possibility that the Voices are levitating storm giants one of whom is a sorcerer who knows Invisibility.
How many big, intelligent, winged dragon-type creatures are there other than half-dragons and true dragons?Now, "draconic creature" can mean a lot of things in any D&D world.
But why would Dorukan even need a throne room? Otherwise sure it does. However, if Xykon reshaped the room to look more like him, we can't know for certain that it was not sealed previously. Also, it would make sense for Dorukan and Lirian, the only people who could, in fact, do maintenance work on their Gates to leave them accessible, while Soon believed that only the honour of a paladin is unbreakable, so the Guard is a better defence than a wall or a hidden room/cavity. That would only leave us with Girard, whose Gate was not, in fact, accessible, since it was encased in lead and stone.