Anyone have any additional details on Bebop + Rocksteady's roles?

I heard that they were originally going to be in the film, but that Kevin and Peter objected and they were replaced with Tokka and Rahzar ... and that's pretty much it. I think I also read somewhere Rocksteady and Bebop were going to be even stupider than they were in the cartoon, but I can't remember where ... probably at the same place I read about Shredder's other daughter in the original comics. Not Karai, but someone else who, if I remember correctly, looked sort of like a dominatrix.

"There is no escape, John!"