The reference to Jesus Christ as the Last Adam can only be referring to Him as the Last Representative of the human race. There will never be another. Just as Adam represets the human race and his actions are attributed to that race making all guilty of sin, (Rom.5:12) so Christ represents a new race, that of the redeemed, and His actions are attributed to His race making them righteous. (Rom.5:19)
I might have worded that slightly different, but close enough to say I agree
The reference to Christ as the 2nd Man is not as clear. .... Quantrill

Is there a reason you can't believe a writer might actually word a sentence for clarity?