After soiling myself, I'd regroup...
Then I'd try seeing just how mobile that thing is. From the video, it looks like you MIGHT be able to retract it cephalad enough to do a really low trach.
I think you go with very minimal sedation and try an awake trach.
How do you say "Hold still little girl, you're getting an awake trach!" in Vietnamese? She is 15 years old, so she might cooperate.
You MIGHT be able to consider an awake nasal fiberoptic, but she's likely 100% dependent on those nares being patent, and I'd hate to booger them up.
Curious what other bright ideas are out there.
I am not sure a tracheostomy is going to be technically possible in this case.
I say keep her in the sitting position, do the best topical anesthesia you could to the nose and upper airway and go down with a small FOB, you might get lucky and find the airway, spray some lido on the cords and intubate.