Going by the Constitution, there's no requirement that the master be human, only that ownership may only be transfered to someone born of human parents. The Master could probably test whether or not Oscar's dad was human by attempting to pass the hotel to him.
if the hotel can already identify such a thing, it's then just a matter of writing a contract. like, make some kind of room that is only accessible if you have certain characteristics. we know the hotel is capable of such tricks, like making sure you can get back to the lobby if you think of it. or get you somewhere specific if you take a specific combination of directions. the layout of it doesn't need to make physical sense of it's locations.
I wondered how human detection could be used in some way or some mechanism that benefits the hotel or can be helpful to someone in some way. Like what good can be squeezed out of it. Maybe there's a practical use of it for security or safety or for everyday purpose or something. It's got to be something it could be useful for other than just a rare thing like determining one's origins.