FYI- The IDW pre-2009 Trek comic crossed over with TNG; Data was there and functional 10 years post- Nemesis. B4 had rebooted and became Data, Picard was still Captain and Geordi helped build Spock's jellyfish craft.
Since Nero came from the original timeline, so did these characters. Whether these guys continue into the alternate JJverse is unanswered but doubtful in the same form.
Bob Orci was deeply involved in the production of these comics and they are considered to be JJverse canon.
FYI- I am familiar with the Countdown comic. I am aware that Data was resurrected in that storyline. I was under the impression that Picard was not a captain, but a diplomat or embassador.
I don't have strong feelings about elements from Countdown; some things I like, some things I casually question.
But if we're talking about Countdown as lending weight to there being precedent for TNG characters crossing into "nuTrek's" TOS era, let's review the characters that do cross over. Nero is an original character who is not strongly associated with TNG's era. Most of the audience for Star Trek (2009) would not have read the comic, and wouldn't have a predisposition to connect Nero with TNG era. Then there's Spock, a character who, spiritual and thematically, belongs to TOS era. In one sense, he has returned to a place and time that is home. Extensive usage in the TNG era beyond a certain point would be intrusive.
So Countdown does not sway me in this matter.