>>3274042Derpy was confirmed to keep appearing during season 3.
What they didn't confirmed is if she was going to keep getting lines or not.
Hasbro loves Derpy as fuck, lately she has been appearing everywhere and she even got a comic con exclusive toy that will seel for thousands of bits on EBay.
While I'm on it, the Doctor was also confirmed by Hasbro (But they registred his name as "Doctor Hooves" to avoid problems with the BBC)