JONNY DOUBLE - private eyes have never really regained the popularity they had in the 50's and 60's have they? For that very reason, I can't see Jonny showing up any time soon.
JUDOMASTER - a new Judomaster turned up in the pages of Justice Society of America before the whole Flashpoint thing and while the character wasn't an influence on Watchmen, with the whole Before Watchmen thing giving a little more attention to the old Charlton characters, it wouldn't surprise me if he showed up somewhere. He's in the possibles.
JUSTICE LEAGUE OF AMERICA - well, yeah, this was DC's flagship title as part of the New 52 relaunch so it's already in place.
JUSTICE LEAGUE OF AMERICA HEADQUARTERS - a version of the HQ is in place (obviously) but I'm not counting it because it's a building people!
JUSTICE SOCIETY OF AMERICA - for a while there was a big fear that the JSA were no more post-Flashpoint. As it is, we know Earth-2's coming soon (may even be out by now - I'm writing this at the end of Feb!) so the Society is in place in some form or another.
JUSTICE SOCIETY OF AMERICA HEADQUARTERS - oh for goodness sake.
J. WILBUR WOLFINGHAM - it wouldn't surprise me if Grant Morrison threw this guy into Action Comics for a laugh, but I don't think it likely.
KALIBAK - as I write this, I have yet to see the end of the Justice League's first storyline so have no idea how many Apokoliptian beings have come back apart from Darkseid. I'm going to err on the side of caution and say we won't see Kalibak before the end of 2012.
KAMANDI - we kinda / sorta saw Kamandi in the pages of Countdown and Final Crisis but with all that being swept away post-Flashpoint I can't see this poor kid making an appearance in anything other than re-prints for quite some time.
KANA - another wartime character that might get a mention in G.I. Combat but not one I'm confident of.
KANDOR - again, something that will almost certainly appear in the Superman titles at some point but, because it's a place, I'm not counting it.
So in summary, two already in place (Justice League and Society) one definite (Jor-El) and one possible (Judomaster)