Hi George, and welcome to Websleuths.
I was just looking at this case again a few days ago. This unidentified female has a unique enough smile that she shouldn't be hard to recognize if we had the right missing person.
She had a crooked philtrum (i.e., the vertical groove between the nose and upper lip). It doesn't say anything about a repaired cleft palate, but it seems that her appearance would be similar to how someone with a repaired cleft palate would look. Actor Stacy Keach comes to mind as an example of someone with a deformed philtrum.
The NamUs casefile Dentals section describes a girl with an "open bite" (meaning that it is difficult - or maybe impossible - to bite down on anything with her front teeth), and an "overjet" condition, which indicates protruding front teeth more severe than an "overbite". I would guess that she probably spoke with a lisp.
Just a few days ago, I was looking in the 1987 Deptford Township HS yearbook for a girl with a lopsided philtrum, and protruding front teeth and open bite. That was the only year available in Classmates.com from that school for that era. The photos in that book weren't very clear, but I only saw a couple of girls who even remotely might have fit the description, but I decided that they were doubtful as being our Jane Doe.
Looking through the MP's I saw one girl whose teeth looked like they might fit the description (but I see no indication of a deformed philtrum).
Brenda Cecilia Crowley
http://www.charleyproject.org/cases/c/crowley_brenda.html
But she went missing 10 years before the remains were found. There was still hair found with the remains, so the Jane Doe probably had not been dead that long. It's possible though that Brenda could have been on the street for several years before her demise.