For the cover, since I gave it a JSA title, I'd go with the JSA cover, from issue #67. In truth though, I'm partial to the Robotman or Dr. Fate covers. The JSA cover is the better choice though, even though it would imply that each character on the cover would get their own origin in the TPB. It'd be a little bit misleading, but not entirely a cheat, since it's the cover for the JSA story that would be inside.
Would you buy it? Let me know in the comments, and thanks for reading.