Yep I see what you are getting at - sort of saying that the initiation of the divorce proceedings established that the couple wanted to be separate and this was done "in court". There is the problem of the August 2013 false start - but let's imagine some proof of that could be found. Technically that is not legal separation which is a legal agreement covering certain matters such as access to any kids, who will pay the bills during the period of separation and so on. So - if they stick to the definition precisely, then in my view "legal separation" was not the right choice on the eDV form. To be honest, I can't imagine they would recognize the legally separated status at all unless that was based on the precise legal status (with a court recognized separation agreement) - but to take Susie's point legal separation may be defined differently in different countries.
So - if the three of us (Mom, Susie and I) were judges on a immigration.com TV show I think we would have a 2 to 1 split decision on this (with me in the minority) - and the advice to the friend would therefore be take the chance (but be aware of the risk).
Link on legal separation versus divorce.
http://divorcesupport.about.com/od/separation/f/legal_separatio.htm