At first, it may seem that this is a strange sentence. However the interlocutor is clearly familiar with that class of houses whereby one disappears and ceases to be the moment one steps through the door. Given the experiences this person has faced (dearly loved family members, friends and even enemies disappearing into the void) I would say this is a very prudent question.
Sein is to be / to exist.
If it was just a general 'stay' while the occupants were out, bleiben is to stay / to remain.
If you wanted to spend the night, you'd use übernachten.
"stay" implies that there is a longer timeframe in which you want to be there. "Be" is about this moment. Here you might ask if you broke a law by entering or if it is really "your" house in which we are. That is not easy to say without context. And it is not a sentence one would often use in German or English.
I hope I could be of help.
Thanks! I think it would be clearer if the phrase was "Dürfen wir in deinem Haus sein?" or maybe "Können wir deinem Haus betreten?".
"Können wir dein Haus betreten?" here you have to use accusative, as the house is the target and not the place where you act.
This context would make more sense to me if there was a word explaining that - eg "are we really in your house?", "can we possibly be in your house?", and so on. As the translation is written, I don't really have a concept as to what they might really mean.
Isn't this sentence's meaning similar enough to "can we go into your house?", or is there a major difference (other than this sentence not including the verb gehen)?
Can we go into your house would mean you want to enter the house right now. That would be "Können wir dein Haus betreten?"