I think you are reading way too much into this and wasting way too much time on it. Khan is a very common surname of people of Pakistani descent much like Patel is a very common surname of people of Indian descent.
While I cannot say for sure, this appears to be Henna Haque, shown on page 14 of this school’s newsletter, pictured with her husband Murtaza Haque and their daughters, Rania and Amira.
http://wsmsnyc.org/home/wp-content/uploads/2013/01/GB_Fall_2011_NamesOmitted_opt.pdf
I think it’s fairly safe to assume that she took the surname Haque when she married her husband and that Khan was her maiden name. But again having that maiden surname does not mean any relationship, either a family or a professional connection with Khizr Khan.
In my opinion (and forgive me for mixing metaphors) you are chasing down an empty rabbit hole with this and there are much bigger fish to fry.
It didn’t take that much time.
By the way, her name was Haque when she was CEO of Ahmed & Yau. In 2010 when the partnership became Khan & Yau she remained CEO. It’s unlikely that she would use her family name in Khan & Yau since her name was Haque prior to the formation of Khan & Yau.
As for Khan, Khizr Khan is a moral degenerate who uses his son as a human shield. He attacks on issues having nothing to do with his son’s death, while using his son to shield himself from criticism.