The following people helped me with the unknowns throughout this site or pointed out where I'd gone wrong or had missed things - thanks to everyone!
Adam Prior for naming several Legion members in issues 1 and 6, and for pointing out the Zorro reference in issue #7.
Andrew Rubio for correcting the identification of Overman in issue #5.
Brad Bice for identifying a character in issue #2.
Graham Stevens for identifying several characters.
Graig for identifying a couple of characters.
The Great Gonzo for the names of the Earth 97 heroes in issue #6.
Justin for identifying the last but one character from the Metropolis battle in issue #7.
Kara O'Connor for naming just about everyone in the two page spread of the church scene in the Collected Edition.
Kyle Theobald for identifying Cliff Carmichael and the Thinker in issue #2.
Mete Guner for sending me another Crisis on Infinite Earths pastiche (Witchblade #128)
Michael Bond for identifying several Green Lanterns in issue #7.
Nicola Boden for finding two more Crisis On Infinite Earths pastiches (Young Justice #35 and Uncle Sam and The Freedom Fighters Vol 2 #8).
Perry Beider for information on the numbering of Earth 154 in issue #6.
Rob Rogers for identifying a couple of characters in issue #2.
Scarlettspiderg for identifying loads of characters in the first four issues.
Simon Barnett for clearing up why Kate (Manhunter) Spencer vanished in issue #5.
Steve Kinsella for identifying Alan Scott and Red Tornado as the miscoloured characters in Page 17 - Panel 4 of issue #6 and for finding the last unknown in issue #4 and the last one from Earth-462.
Thomas Parks for a huge amount of info, particularly the Aquaman characters in issue #3, and for highlighting changes in the Collected Edition.
Tomas for identifying number 25 on pages 2-3 of issue #7, as well as correcting my misidentification of Major Disaster in the same issue.
Zakarias Triunfo for identifying several characters, particularly the Old West characters in issue #6 and the final character in the Stonehenge ensemble.
zaurieljl for identifying several characters throughout the entire series.