I do not recall reading anything about a couple that lives "In The Shops"
Regarding the question of SN :
http://www.nbcdfw.com/news/local/Search-Efforts-Continue-for-Missing-Fort-Worth-Woman-274404321.html
Steven Nickerson was with Morris before she went missing and said she seemed a little upset that night, but he didn't know what was wrong. He said she insisted on driving back home to Fort Worth, but he never realized it would be the last time he saw her before she was reported missing.
Does not say or confirm there was any party he himself attended.
The man in question walking with Christina :
http://www.nbcdfw.com/news/local/Vigil-Held-for-Missing-Woman-Christina-Morris-275692101.html
Morris, 23, was last seen in the early-morning hours of Aug. 30 at the Shops of Legacy shopping center in Plano.
Surveillance video from the shopping center shows Morris and a man, who has been described by family members as a friend of Morris' from high school, approaching a parking garage. Plano police have said their
detectives have questioned that man, as well as several other people, and that no one has emerged as a person of interest or a suspect in Morris' disappearance.
None of the searches have produced clues in Morris' disappearance.
I can not say he has been questioned extensively , detectives did question him as well as several other people.