"Unusually clever AI"; yes, that's interesting, but ... If your game were a cake, the clever AI would be the taste, and I cannot taste the cake if I don't eat it. So, what makes me eat the cake? The appearance, probably. The frosting, the cream, the decorations. I remember how much I like this kind of cake, and I bite. So what is "appearance" in your game? It may be interesting and intriguing screenshots or gameplay videos, but mostly it is motivation conveyed, for instance, by an interesting story. As Redonihunter said before me.
The story tells me why I should enter this house and brave the horrors in it.
Is there a treasure? Rich great aunt Marbella, the old witch, died and left me nothing in her testament but I know the money must be somewhere. She didn't trust banks, so it must be hidden in her house. And she was more than a bit mad, so her keeping a strange house pet wouldn't be surprising either.
Persons in distress? I received a strange letter from an old friend; he/she urgently needs my help. I'm no hero and have other worries right now, but he/she once saved my life, so how can I deny him/her my help? And it's not much he/she is asking: just retrieve an old picture from an abandoned house.
A stupid bet with a peer? Yes, I was drunk and Jack knows exactly what buttons to push when I'm in that state. I could forget the whole thing if not for my pride. I'll show the little bastard that I'm not afraid of entering that accursed house if it's the last thing I do.
And so on. As Redonihunter already said, it must not be complicated, but it must convey a motivation for our player to enter that house.
About the model. In the first story, it would fit as it is: great ant Marbella's cute little pet. Otherwise, there are a lot of free characters you can choose from in the Unity asset store.
I hope you keep on working on your game: make it interesting and scary as hell!