I don't think anyone has actually verified if LEK graduated, but she claimed she had on her resume, & the family has said they found her college records in her personal papers after her death. (They were in another file drawer that she told B not to look in. Sorry I don't remember the post this was shared in, but I know it was in "General Discussion and Theories" #3 thread.) So the circumstantial evidence is pretty strong that she went to those college & graduated; if she hadn't I would expect that either Velling or the Ruffs would have said so since that would be another clue.
And it's very easy to think she had a chronic, long-term mental illness, due to the lack of a personal history & her notorious end. But when I looked at all of the meager evidence for her life in the Houston area, nothing really stood out: she lived in some sketchy apartments at the beginning -- but anyone new to a city would do that -- & while she moved once a year to a new address, they were always to a better apartment (based on Yelp reviews) & once she moved to a decent one she stayed there for several years. They portray a person who, while struggling with paying bills, wasn't exactly poor or living the high life off of stripping. In many ways LEK was very average & unremarkable -- like countless thousands of other young women living in the Houston area.
And she did get a speeding ticket. I posted some of the information
here back in December. The resulting discussion provides a lot more information.
As for the fact that no one remembers her... we have had the occasional person who dropped in, said they remembered her as a casual acquaintance, then vanish. (And then there's Spring/Summer1988. Form your own opinion about that those posts.) So it's not as if she were a complete ghost. Yet you have touched on an important point: LEK had no known close friends. Any she had after marrying B would have been contacted by Velling or the Ruffs, & mentioned at some point. And none have come forth from her time before she was married. All of which suggest she was either one of those people who was difficult to get along with, or maybe tended to blend into the background. (Sometimes I think I fall into one of these two groups.) The people who knew her best probably either haven't heard about her suicide & her mystery, or haven't connected the LEK they knew with the one who killed herself, & would hardly consider themselves more than acquaintances.
If there was any stress in her life, IMHO it wasn't because she was hiding from her old life, but due to lack of any substantial personal connection to other people. Loneliness can harm one's health, both physical & mental. And IMHO, only someone who had problems making substantial personal connections with other people would sever all connections to her previous identity as well as LEK had, & leave everyone else with a mystery.
I wouldn't be surprised if this case ends up like one of those famous & baffling mysteries like the Roanoke colony or the
Mary Celeste, ​puzzling armchair detectives for generations.