Yes, the 'tradition' is that the Elizabeth Alexander who was married to Matthew Wallace is generally accepted to be one of the Two Sisters in the Seven Brothers/Two Sisters group.[I call this group the 7+2 for shorthand.] I'm not sure if Elizabeth Alexander/Matthew Wallace were the ones who were on the "Wallace Scrawl" tract in/near New Munster, or whether it was their son, Matthew Wallace [Jr] whose wife is 'said to be' Sarah Alexander, a d/o Samuel Alexander/Mary [prob. Taylor].I am now out of my depth in terms of knowing much about these 7+2 descendants.
What kind of information -- or more importantly documentation -- are you seeing that connects Martha Alexander/William Lassley/Lashley (or their daughter, Rebecca [m. Thomas Kilgore] to any of the 7+2 ALEXANDERs??