Not sure how editorial within each company decided on who fought whom for any of the fights (but they do mostly seem logical pairings in terms of fanbase), but the ones the fans got to vote on are:
-Batman/Captain America
-Wolverine/Lobo
-Storm/Wonder Woman
-Superman Hulk
-Spider-man/Superboy
The rest of the fights' outcomes where determined by creative (Green Lantern/Silver Surfer, Flash/Quicksilver, Aquaman/Namor, Catwomen/Elektra, etc.) - Oak
Not sure how editorial within each company decided on who fought whom for any of the fights (but they do mostly seem logical pairings in terms of fanbase), but the ones the fans got to vote on are:
-Batman/Captain America
-Wolverine/Lobo
-Storm/Wonder Woman
-Superman Hulk
-Spider-man/Superboy
The rest of the fights' outcomes where determined by creative (Green Lantern/Silver Surfer, Flash/Quicksilver, Aquaman/Namor, Catwomen/Elektra, etc.) - Oak