One video features Robin and Superboy and appears to tease "Super Sons." As such, the characters are likely Damien Wayne and Jonathan Kent; the son of an alternate-world Clark Kent and Lois Lane, Jon recently inherited his father's powers in the "Superman: Lois and Clark" series by Dan Jurgens and Lee Weeks.
Another teaser highlights Jessica Cruz, aka Power Ring. Power Ring was originally the evil counterpart to Green Lantern from Earth-3, until he died and Cruz assumed the mantle and worked with the Justice League. It appears as though she'll be a Green Lantern following "Rebirth."
A third teaser spotlights Killer Croc and Harley Quinn, who is seen sporting a new costume and holding a rifle. It's safe to assume both characters will be a part of the new "Suicide Squad" series, as they're both slated to appear in Warner Bros. upcoming film based on the property.
The "Rebirth" relaunch starts with the "DC Universe: Rebirth" one-shot scheduled for release on May 25, written by Geoff Johns and illustrated by artists including Ethan Van Sciver, Gary Frank, Phil Jimenez and Ivan Reis.