We do have some evidence, but it isn't quite clear at the moment.
Evidence 1: During a convention, fans asked for information on whether Rocksteady and Bebop would appear. Ciro Nieli simply said "Be patient", indicating that Bebop and Rocksteady will appear at some point in the near future.
Evidence 2: Bebop and Rocksteady's names are seen on a list of leaked toys in the current TMNT toyline. They are clearly not the Classics figures because those were released in 2013 and the list was of toys that were released or are scheduled to be released in 2014. Adding to this is the fact that Kirby's bat mutation and Rahzar recieved toys before they actually appeared in the show and that there are figures based on the Turtles' LARP selves in the upcoming episode Mazes and Mutants in production.
I would like Bebop and Rocksteady to appear in the new show, but I am not completely sure if they are even necessary. I mean, not every adaptation has to include all the previous characters!
At the risk of backlash from other wiki contributors, I have the same attitude regarding Venus de Milo. The Next Mutation was not good, but I am one of the few fans who believe that Venus can be reworked into a better character. As with Rocksteady and Bebop, I would like Venus to make a comeback, but I am unsure if she is necessary because the show's version of April already has a lot of similarities with her (they're both teenagers, they're both treated as the fifth member of the team, they both have ponytails, they both use the tessen as their weapon, and they both have latent psychic powers).