Just for the heck of it, let's pretend there was yet another "Crisis" which went and altered DC's past.
In this new reality, seven heroes formed the "original" Justice League of America.
Basing it primarily on previous versions for the "original" founders, which seven would you choose from the following list:* Aquaman (Arthur Curry)
* Batman (Bruce Wayne)
* The Flash (Barry Allen)
* Green Lantern (Hal Jordan)
* Martian Manhunter (J'onn J'onzz)
* Superman (Clark Kent)
* Wonder Woman (Diana Prince)
* Green Arrow (Oliver Queen) - 1st new member to join
* Black Canary (Dinah Laurel Lance) - initially replaced Wonder Woman in post-CoIE continuity
* Triumph (William MacIntyre) < Justice League America #92 (September 1994) / Zero Hour >
* Cyborg (Victor Stone) - founding member instead of Martian Manhunter in New52 continuity
* Plastic Man ("Eel" O'Brien) - see Justice League of America #144 (1977)
* Rex the Wonder Dog - see Justice League of America #144 (1977)
* Robotman (Dr. Robert Crane) - see Justice League of America #144 (1977)
* The Vigilante (Greg Sanders) - see Justice League of America #144 (1977)
As mentioned above, there were the original "original" seven members; then Green Arrow was the first new member to join the original Justice League of America; after CoIE, when Wonder Woman hadn't yet left Paradise Island when the JLoA was originally founded, Black Canary was retconned into her place; for Zero Hour, Triumph was added as an original member who was later forgotten; and for the New52, Cyborg took the place of Martian Manhunter as a "founding member".
As for the other choices I listed, those heroes were among those present in Steve Englehart's 1977 story "The Origin of the Justice League-- Minus One!".