The ESTJ typing is clearly wrong. Stewart described herself as being awkward, shy, and a loner as a kid. Watch some interviews of her and its evident that she has strong social anxiety. She is extremely mature and serious, even as a teenager, a trait correlated with introverts. We can conclude that she is Ixxx. She describes herself as a logical thinker in this interview ( ).
We can conclude that she is IxTx. Now note the way that her eyes dart around, looking at seemly random places but rarely at the interviewer/speaker. This is a physical trait correlated with strong intuition (Tracking eye movements) We can conclude that she is INTx. For everyone claiming she is ISTP (TiSeNiFe), where do you spot Stewart's dominate Se function? Ask yourself this, Is she aware of her physical environment? Or does she seem like she is in her own head? The answer is pretty obvious to me and it's not close. If anything, a argument for INTP/INTJ seem to make more sense because we can rule out ISTP entirely.
If anyone finds evidence contradicting what I'm saying then please post. Playing the guessing game is just so meh, better to investigate her cognitive functions. I think she is INTP with extreme Ti and less Ne than most. I linked more clues below, her personality is fascinating.