I guess the reason I had the impression the friend Maggie went shopping with and the one she planned to meet later were different was that it's reported Maggie went home with the friend after the trip to Walmart but then returned to her apartment.
But, I do see in the following article that the friend Maggie went shopping with received a text from Maggie at noon, after she'd returned home. That does leave plenty of time for Maggie to go home and do other things before going out for the evening.
http://www.wcnc.com/news/local/Maggie-Daniels-friend-remembers-her-final-day-266651331.html
A neighbor, M F, who was also a former student, saw Maggie when he was taking out trash Friday (27th) but doesn't give a time. He told her to have a good day, so it's likely he saw her in the A.M.:
http://kticradio.com/news/national/index.php?more=34914286
A maintenance worker at the apartments, J M, saw Maggie returning home "around lunchtime Friday", which agrees with the timeline given by the friend who accompanied Maggie to Walmart. Only, he reported she was wearing black sweatpants. Either he was mistaken, thinking of earlier that AM or another day, or Maggie could have changed into sweats after the Walmart trip. The friend lived nearby, so maybe Maggie walked to her house, rode with the friend to Walmart, and then jogged back home from the friend's house. She may have taken the sweatpants with her, or bought them at Walmart (curious to know if she did).
http://www.wsoctv.com/news/news/local/medical-examiner-foul-play-suspected-teachers-deat/ngWth/
Did anyone see Maggie after she returned to her apartment shortly after noon?