Interesting.  Perhaps the term "lynching" may not apply to some you mention, as something of "due process" put individuals on the gallows.  You include five Tsilhqot'in warriors hanged by Judge Begbie back in 1864 as "lynchings", too.  Some would agree.  The "murderers"--as they were called--thought they were at war, and came to surrender.  (Uh-oh.  Bad move on their part...but likely no choice as the people were starving.) Maybe that's why, over a century later, BC made a formal apology in Quesnel, site of the hanging--er, "lynching."

Yeah, don't have much doubt that many might be undocumented.  Except that...if any are "undocumented" how does anyone know they exist?  Just asking...