^^
Those are mostly 2024 candidates. Maybe Booker in 2020 if he's elected governor next year, but otherwise those guys would probably wait until 2024. (I know I listed Newsom and Harris as possible 2020ers, but as Joementum pointed out, 2024 is more likely.)
I think you're pretty much right. Like I said, I was trying to avoid candidates who are already being speculated to run in 2016. I will say, though, that Booker and Cordray have a significant chance at unseating the republican governors in their respective states (Christie in NJ or Kaisch in OH) by 2014, which would give them time to build credible national profiles. By the time the 2020 campaign season starts up, both could already be re-elected and serving second terms, and will have real records to run on. Baldwin is a bit of a long shot because of her sexual orientation and outspoken liberalism, but if a republican wins 2016 and support for gay marriage continues to climb, she has a shot by 2020. I do agree it could be quite some time before the rising stars in NY and Cali make it to the national stage, if only because each state is dominated by democratic incumbents. Castro has to wait it out until Texas starts becoming more of a purple state (either 2016 or later) before he'll be a serious contender for statewide office.