Asking if we are still somewhere would imply that we've already been there for a relatively long time. So, I can imagine boarding an airplane and dozing off shortly after I get into my seat. I might wake up and find that the aircraft is still on the tarmac, perhaps due to a weather delay or mechanical problem. In a situation like that, I might say bemoaningly:
Oh, are we still here?
I suppose I could substitute yet for still in that sentence, and change the word order:
Oh, are we here yet?
I think that's grammatical; however, as others have said, it would sound like I'm auditioning for a Shakespearian play.
If we really wanted to use there instead of here, we could imagine it's my uncle Ebenezer who is stuck on the plane, and he just texted me to let me know he is still in Chicago, even though he was supposed to be taking off almost an hour ago. In that case, when I share the news with my family (who are all anxious to see Uncle Ebenezer), one of them might cry out in dismay:
Oh, is he there yet?
Oh, is he still there?
but again, it would sound dreadfully old-fashioned and melodramatic, and therefore I can only imagine it said that way for humorous effect.
Now, as for your wording: because "we" is in the first person, and "there" often refers to some place away from the speaker, I'm having a hard time construing a scenario where the actual sentence would be combine "we" with "there" as you did:
Are we there yet?
unless there refers to a figurative place rather than a literal one. Perhaps you and your spouse are still arguing about a long-time bone of contention, and you, tired of the argument, say:
Are we having this fight yet again?
Would could become shortened to:
Are we there still?
Are we there yet?
But if that's the way you said it from the outset, I'm not sure how well-understood you'd be. You might even start another long argument.