3  of  them  are  worth  developing because they  are  part  of  fusion's.

You  will  need  to  develop  them  to  be  used  as  Fusion  material.

Worth developing: no.

Worth keeping: yes, the fusion champs. Rocktooth and Raider are part of the Rhazin fusion. You should not sacrifice them.

As an early game champ, Diabolist isn't too bad either. I wouldn't invest much in her, but she's worth bringing to at least level 40 so that you can eventually turn her into 5* food.